A great general info site for both
AC and
AC:WW is:
http://www.animalxing.com/It really helps when looking for a fish you need or a bug to catch.
For
AA:WW players:
http://acww.scarymachine.com/After signing up for their forums by clicking the purple/blue talk icon up at the top right (don't bother posting, the site's a little lifeless), you can use their cataloguing system. By checking off the items, accessories, bugs, fish, fossils, paintings, paper, and so forth that you've gotten; the site can:
-Show progress in specific collection areas (or on a whole) with progress bars and percentages.
-Generate a checklist for printing that you can use while you play for quick reference on things you haven't bought and such.
-Advertise your town's progress to other Scary Machine AA:WW users.
I created my own checklist and printed it. Now when I'm not next to the computer I can still be sure I'm not buying anything I don't need to. I also make notes on the few fish and bugs I need to catch.