I like to have one entire session each job dedicated to legwork, but with 6 players sometimes some of the players feel left out. Here's a rundown of my players.

1. Hacker with some Triad connections.
2. Rigger/Hacker, emphasis on Rigger. Can't do much else.
3. Troll mage. Combat and manipulation focus.
4. Cyber ninja.
5. Elf face extraordinaire.
6. Street doc with a slightly psychotic bent.

Any suggestions on general ways to make sure they all have work to do when it comes to prepping for a job? I can provide more info about players if needed.

Well for once don't limit the legwork to the hacker making data searches and the face talking to his contacts.

Make sure the party needs to talk to certain individuals in person, people who might not want to talk to them (this is where the combat chars come into play).

Despite everything you do you're not going to be able to have all 6 actively engaged in legwork at the same time, and this party is bound to split up.

...first off I would play up the PCs' contacts. I have the players in my campaigns give me a short paragraph on their contacts, not just the basics but also a bit about their personality and background.

Maybe have some of the legwork take place in a seedy area, gang turf, or a known underworld hangout. This way the Rigger and Sammy will feel like they have more of a purpose. Also, Faces and Deckers (sorry) aren't the only ones to do the talking and researching. Have the Sammy chat up a bartender, have the rigger use drones to do a bit of recon or overwatch. One of the things a Rigger/Decker character did in a campaign I ran was jump into the traffic cams to trace a vehicle. He did it by backdooring through a Trivid news station which had access for their traffic reports.

Another thing is what knowledge skill do they have. These could be another basis for legwork.

Do not, under any circumstances, downplay the importance of classic detective work. Door-to-door canvasing, investigating leads, finding clues, stakeouts, planting bugs, all of these can be made important.

A ninja, presuming that he has some stealth skill, can be optimal for stakeouts. The rigger's microdrones, assuming he has some, make perfect eavesdropping devices. The combat mage can be a great interrogator, cutting to the chase by using control manipulations of compel the truth or just using mind probe to get to it directly.
The Street Doc can cultivate a network of street contacts fairly easily due to the demand for his services.

There are a lot of angles that you can look at things from, and the runners should be hitting as many as possible. Things I can think of:

Investigate every name you come across to see what angles they have and how you can exploit them
Talk to the neighbours
Drone surveillance
Matrix investigation
Get your contacts involved (usually by offering a small fee if they find anything)
Abduct/interrogate somebody (this can get you info, uniforms, keycards, etc)
Check for magical defenses/astral trails
See if knowledge checks apply, even if they don't appear to (finding out the guy you were going to extract has gang connections can give you an ally, or warn you about a potential enemy)
Create a false alarm situation and see how their security responds. (See the movie Ronin for a great example)

Some of these are only useful for certain types of runs, and some are purely situational. A snatch and grab can make the entire run easier, or could warn the target and make it almost impossible.

Encourage your players to think outside the box.

Don't make games requiring legwork with 6 players. Or at least don't expect them all to feel involved. Or have some of them investigate the XBOX for a while.

Like Dork basically suggested, if you want to get them all involved in the occasional bit of legwork, turn that legwork into an adventure in and of itself.

Take some time to look at the contacts that people have and see about leaning on the corners that the Decker and Face don't have. For example, maybe teh Cyberdoc has a Tanamous thing ... run something where he's the only guy "Who knows a guy" who might know something.

Another option for promoting legwork for the whole party (and oddly this is the only positive application I've seen so far) is bigotry/racism.

The elf face should have the easiest time with social interaction, but don't forget that many people in 2070 still have issues with metahumans. Not necessarily all, some just don't like elves. Or dwarfs... or trolls... or humans. You get the idea.

So that brings your troll into play if the people you're talking to prefer trolls (I can see orks and trolls preferring to deal with another troll). Or the cybered up characters could go look for information in one of the cybered-up bars. If people today put so much effort and money and time into classic cars, there's going to be a small section of society that is not only proud of their chrome, but they want people to see it. And they want to show it off in someplace that appreciates it, hence the cyberbar. Like the decker bars of old, non-deckers had a rough time not only fitting in (different styles of dress, different etiquette, etc) but they couldn't follow the conversation as it was too specialized/technical/jargon-filled.

Finally, there's profession bars. I know this in real life, there are bars that *bartenders* like to frequent after a shift. I'm sure you could easily stat (heh) a DocBar, or anything you can think up. A hacker bar might not be as popular as it was when people couldn't hack you from across the room, but a rigger bar will always be popular.

People love to associate with others like themselves. Cliques exist for that reason, and legwork should reflect it. The elven face isn't the best choice to talk to the crusty dwarf rigger (dammit, when I ran smuggling runs we had physical connections to our vehicles! And control rigs that were massive! They weren't no tiny mod, it was invasive fragging surgery to get one installed! You kids today...) for obvious reasons.

The only bar prototype that fails at concept is 'NinjaBar', since there's no one in it, ever. The owners would close it after a week when all their booze mysteriously vanished and they made zero money. Plus the cost of cleaning up all those damn cherry blossoms...