You'll no longer be able to use Epson Scan as it's a PPC application.
OS X comes with an application called Image Capture that you can use to scan documents. This application should open automatically when you press the main scan button on the scanner (the one with the green LED).
You can change what application this button will open in the Print & Scan system preference. There doesn't look to be any provision for the other buttons though.
Hi, I was not able to use the epson scan software after upgrade to Lion from SL.
Just redownloaded and reinstalled the 2009 intel version of the scan software from the Epson support's site, and everything is fine now.