So, abbeyrd mentioned LibraryThing a while ago, and I poked around with it. I also bought Delicious Library, which is pretty fancy, and I'm tickled that they work together.
Or, I hear they work together - I haven't actually tried yet.
I'm sure a fair number of folks already know as much as I do about these two tools, and a sizable slice of the remainder availed themselves of the links. For the remainder out there - these are each means for keeping track of your book collection, with potentially room to also track CDs, DVDs, and other libraries of stuff.
Delicious Library is a polished tool that runs on the Mac, and connects up to the internet to do lookups when you enter a new item. A fancy thing that it features is the ability to use a webcam as a standin for a laser scanner, and thereby read the UPC barcode as a quick means to import a title.
Delicious Monster (the folks behind Delicious Library) also sell a bluetooth compatible scanner, which sounds super cool. I haven't yet convinced myself that it's in the budget just yet, so I've held off.
I have been poking around with LibraryThing, and it seems to be an interestingly similar tool. All on the web, so your information is available to you from all over the house, not right next to the Mac. Or maybe you're at Barnes and Noble, and you have access to the internet on your cell phone. Bam! You also have access to your library catalog. I can imagine that being convenient.
So. I got my CueCat scanner today, and it's a silly piece of plastic, but it works great. I've hit the edge of my free account - it's super easy to scan books quickly with this device. I think it's about time to pay for the membership and start integrating my Delicious Library catalog with my LibraryThing catalog.