The rest of the "finders" series are good, but not at the same level of simplicity as Tree Finder. It's pure genious. I sent the publishers an email last year encouraging them to produce a PDA version. Wouldn't that be a fun Palm app! They were in the process of digitizing their film and were mildly interested, but I doubt they'd dedicate a ton of resources on such a project, even though I'm sure they could recover their investment quickly.

Along that same line, have you seen the NWF Handheld Guide to Birds ? Real slick and at $65 it's a good deal even though that's a lot of bucks becasue it comes loaded on a 128MB card, which would cost almost that amount anyway. The only reason I haven't bought it yet is I asked if I can purchase and add individual birds. Our troop camps in IL, WI & MI and the product is sold bu state, which isn't bad but there are few species in one state that are missing from the others. I wanted to add the differences to create a regional "Great Lakes" version. I never heard back from them and didn't follow up. I guess I should simply choose Illinois and move on. Check it out. They have a demo with a handful of birds you can download to test.