Good App for keeping track of books?

[Shangri-laschild]

I know that there are a lot of readers here and while I don't know how many people use iphones/ipads/etc, I thought it would be worth a shot. Anyone have a good app that they recommend for keeping track of books? I've been trying out a couple and the ones that have the feature to scan the barcode to enter in the book give me even better hope about the idea of actually keeping up with an app like that but not all of them have that option.

[Crossbow]

I use GuruLib for my cataloging use. Since it's web based, I can access it anywhere, and has the ability to take scanned barcodes and enter the record. It also can use a picture taken from your camera phone and enter the data that way. Includes full lending support and works for multiple types of media. Libraries can be exported for offline use as well.

It's not a mobile app itself, but it works well enough under most circumstances that I haven't needed one.