I use one called Expense Diary on my Treo. It's far better than a full-manual option, but not nearly ideal. For instance, it doesn't sync with Excel, so I still have to fill in the report manually. But it's at least a way to make sure expenses get recorded and categorized as they occur.

It was a major gripe of mine that the Treo did away with the expense report app that had been standard on prior Palm products. And there were even third party add-ins to transfer that data automatically into Excel.

Now I'm on the verge of dumping my Treo for a Droid, and your post has reminded me that I need to find out if there's a decent expense app for Android devices. So to add to the OP's question, anyone know of a good Android expense app?