The way I obsessively checked my iPhone over dinner last weekend, it was pretty obvious to my friends that there was something extremely critical that was going to need my attention soon. Life or death, actually.
This was serious. I needed to win that Timbuk2 messenger bag. There was absolutely NO WAY kelc_123 was going to snap it up from me at the last minute... NO WAY. I refused to even consider the possibility of pausing the bidding war and enjoying my chicken curry. And thanks to eBay for iPhone, I was able to swoop in at the last minute -- when she least expected it -- and swipe it right out from under her nose. Winner.
The app overall is pretty simple, and free. You get an at-a-glance overview of your activity on the home page, and a bit more detailed view on the My eBay page. You can search for and buy, sell, or watch... all the really important stuff. Only major downfalls I found: no messaging or ability to ask a seller a question. Check out the CNET review of eBay for iPhone for more details.