There are several sites out there that are designed to help keep track of your travel rewards programs (Points.com, AwardWallet.com, etc.).
However, there is also some free software which might work better for folks who prefer to keep all of that personal information on their own laptop as opposed to some site out on the Internet which they have no control over.
Mileport is a Windows application which will track multiple users with multiple accounts. After trying it out I’m hooked. It lets me track all of my accounts grouped and totaled together, as well as all of my wife’s accounts.
Highly recommended, so check it out.
A few features I wanted to mention concerning AwardWallet.
1) Mobile access
2) Google iGadget
There is a screencast where you can see the site and mobile access in action.
http://www.awardwallet.com/screencast/
Cool stuff.