As said before, the largest source is the Tir Tairngire book (7210) published by FASA. Out of print for a while, but Catalyst sells it in PDF format...
http://www.shadowrun4.com/products/product.php?i=7210This book is second edition, so it's only good up to 2054. As far as SR4 updates, Shadows of North America (10655) has some 2060s (SR3) info.
http://www.shadowrun4.com/products/product.php?i=25015 And rumor has it there will be some more updates in the upcoming Almanac.
Portland's terrain & geography has changed little. The freeways are basically the same. The only major additions I can think of were Royal Hill (the residences of the Council of Princes, the Tir ruling government), which sprung up in the west past where Highway 26 and 217 meet, and the Telestrian arcology, in Eastside Portland around 15th and NE Sandy. Of course there is the Portland Wall, which fell into disuse sometime in the 2060s and is no longer patrolled or secured IFRC. The wall surrounds Portland, from the 217/I-5 interchange ("checkpoint charlie") across Lake Oswego to Gladstone, Up through Gresham to Troutdale on the eastside. On the westside, it skirts the west side of 217, up into Forest Park past the St. Johns area, excluding Sauvie Island & across the Columbia Slough (Jantzen Beach is outside the wall.)
In past Portland runs that I have GM'ed, I've basically kept well-known buildings, bridges (except for the Marquam Bridge, I blew that ugly sucker up), and institutions more or less intact (the Tir Tairngire book even mentions that Lloyd Center Mall is still around, albeit the ice rink has been used for more deadly pursuits. Does blood bounce on ice? hmmmmmm.) However, I've added a larger downtown area, more skyscrapers, and a bigger megacorp presence than noted in the TT book. I've even brought back the Shanghai Tunnels as kind of a nod to the Seattle Ork Underground. Portland's nice neighborhoods are NICE. Portland's not-so-nice neighborhoods are a one-way ticket to a boot to the head. The great thing about living in an area that is covered in the Shadowrun universe is you really can have fun making the game your own. Shadow spirits on Mt. Tabor? Why not? That place is creepy after dark. I've even used P-town's history as a springboard for interesting locales. Like the Willamette Stone, used as a starting point to survey and section the entire Pacific Northwest: while its location was chosen for mundane reasons, what if, in the Sixth World, it is a key intersection of ley lines? Portland nowadays is noted for beer, coffee, and indie rock bands, I've kept some of that flavor, too. Nothing like a cold pint of Tir Deschutes Porter after a run in P-town. Most sites and locales I invented, as the TT book contains some sites for flavor,... but you could borrow any club or restaurant from Seattle and plop it in Portland, which is kinda true in real-life 2009. Or keep "real" locations... maybe the Doug Fir Lounge is a great place to meet a Johnson... the adjacent Jupiter Hotel has private rooms to meet in.
Since there isn't much info (yet) on Portland in the 2070s, I have to imagine that it is a city in tremendous political upheaval, and the level of crime and chaos make it a great place to do runs. However, I really recommend you check out the TT book & SONA book, because the politics & society of the Elven nation can be strange and confusing, but has a profound effect on the city. Then have fun coming up with your own stories & locales based on your first-hand knowledge of the city in 2009. You can't mess it up.