Usually, its common to see a focus as a specific object/talisman in a game but i was thinking about other forms. After looking at mauri tribal tattoos along with other cultures, is there any reason why i couldnt make a character which has his or her foci done as magically active tattoos?

No, Tattoo Foci have been canon since, at least, 3rd Edition.
Hell, you can even have cyber-ware foci . .

ok thats what i thought but i wanted to make sure it was canon

There are rules for tattoo

Sorry for the forum necromancy, but can you point me towards these rules in SR4?

I remember in 3E one of my colleagues enchanted some tattoos to add armor to the non-magical recipient and would like to do something similar in SR4.

Tattoos are much harder than merely implanted foci, and no, you can't just give them to random people. The easiest equivalent of that is Quickening a spell on someone. Yeah, I don't know where these 'real tattoo focus' rules are in SR4, myself.

it should be in the street magic.
a special form of anchoring, not it's own meta magic anymore i think

That's where I was looking. The only mention of tattoos is the next page, under Quickening. Besides, according to how Anchoring Foci seem to work, you'd have to 'give your tattoos back' every time you wanted them re-charged.

Hmm, strange . . could have sworn it was under anchoring and had some rules to it soo . .

I want my panties to be my foci. noone will steal them!

Only if it's chain mail bikini bottom.

Let us know if you do find it, anyway.