There are some issues, of course, but according to a friend who tested this for me, most of them work just fine. Since the Amnesty Widget Browser is in public beta, it's free for now -- it will be released as shareware in its final version. Finally, if you decide to remove it, here are the removal instructions.
I tested it under 10.4, and it's a handy little application for managing widgets, but (mainly due to some of the noted issues above), I prefer to just use Dashboard itself. But if you're in 10.3.9, it's the only way I'm aware of to use third-party Dashboard widgets, many of which are quite useful (alternative solutions welcomed in the comments!).

