Sxipper lets you log into any website with a single click. Sxipper saves you time by keeping track of an unlimited number of usernames and passwords and it has a useful feature called personas. Sxipper is different from most password managers or form fillers in its use of artificial intelligence to figure out how to properly fill in web-based forms (with your data) that it hasn't seen before. In other words, when you visit a web page for the first time, Sxipper can often figure out where your data should go.
Here's a nice review of Sxipper:
http://www.canada.com/vancouversun/news/business/
You can download Sxipper here:
https://addons.mozilla.org/en-US/firefox/addon/4865
I like the fact that it is cross platform - runs on Linux, Max and Windows.
Quote from the review: