To see what are hot selling products on eBay you can look one of two places.

The first is the eBay Pulse Page there you can browse by category the top 10 sellers and the top 10 keywords that users are searching for there.

The next one is probably the best product that eBay gives out for free that nobody knows about!
The eBay Hot List that is updated monthly.  It can be downloaded here and lists what is Super Hot, Very Hot and Hot on the site month.  The list comes in pdf format so you can distribute it to your friends or view it using Adobe Acrobat or Preview (OS X). 

All this info at your finger tips to help you sell better and its free!  Enjoy