TechReviewSource.com posted a review of the Apple iPhone 3G S. Here's a taster:

In summary, the Apple iPhone 3G S is a minor refresh and upgrade from the iPhone 3G, so if you're a 3G owner, you really won't need to upgrade since most of these features will be available via the free iPhone 3.0 software update coming on June 17th. However, if you are an iPhone first-generation user or don't already own an iPhone, it is a wise-upgrade in our opinion. If anyone has been holding out on getting an iPhone because of its lack of features compared to other smartphones, now is the time to get one.

One important aspect is pricing, which is at either $199 (16GB) or $299 (32GB) for new AT&T customers or existing subscribers outside of their 2-year contract (which means all iPhone first-gen users). However, iPhone 3G customers are only a year into their 2-year contract, which means you can only purchase a 3G S for an additional $200 on top of the subsidized prices.