I have called four AT&T corporate stores in the Los Angeles area and received the same answer: They can give me another new SIM card, but there's no way to process any downloads to it and they do not have an application called Card Station. Their card readers can only transfer data from one SIM card to another.
One guy who's worked with the store for 5 years went so far as to say that this sounds like SIM card cloning and is illegal. He also said that the activation process and network may be different in Florida than Southern California (where I'm located).
I also called AT&T's main customer service number and they lady I spoke with there had never heard of this either. She did an "over the air" update, but I did that with my old SIM card also an it didn't seem to change anything.
Although I updated to iPhone software to 2.1 after first buying the phone, problems I'm experiencing are that I cannot receive a call while at work in Hollywood 90038 (solid blue 3G coverage for this entire area per AT&T's 3G network coverage map). After saying "Hello" several times, I never hear anything, must hang up and redial. After redialing, the call goes through fine. Calls also drop frequently when walking in this area, and also when I drive to and from home. Calls also drop at home, which is about 2 miles away.
What baffles me is that these calls are all made within metropolitan Los Angeles (even the calls from the other end), where the 3G signal maps show strong coverage. Looks like my options are to get yet another new SIM card from AT&T, which probably won't help any, or go to Apple for a replacement iPhone (word from another of the AT&T Corporate stores here is that Apple will send me back to AT&T, but it's worth a try).
I switched over from Sprint and have 2 days left on my 30-day trial period, so also have the option of ditching AT&T and the iPhone less restock fee, but I do really like the internet features of the iPhone. If I didn't need the ability to make and receive voice calls on it, I'd be pretty happy!