There is a starbucks near where I live, but the wifi there is horrible. Worse, I cannot get 3G, so basically, I go elsewhere. Then AT&T announced they were going to give iPhone users free wifi access. Great! But, you have to go through this silly login process: Link to process.. Whatever. It’s not a chore so much as just plain annoying. So much so, I do not bother and stick with edge.
Well, deviceScape came out with an app called easy Wi-fi for AT&T.  The idea here is, once you entered your info, you can go into any starbucks and after a few min, it will auto log in you in.  Sweet!

The first time I tried it, it did not work, thinking, ‘great, another starbucks wifi fail’.  Well, a week later I tried it again.  Well, well.. it worked!  I then had an afternoon meeting at another starbuck in SF and it failed the first time.  I turned wifi off then back on, and then ‘ta-da’.. connected.

So I would recommend getting this. I would also recommend turning the app on when you are about a block away from the starbucks.  It does take some time to login, so give it as max a head start as you can.