Is there some way to sync bookmarks?

I have a simple idea, but I haven't been able to find any software to do it. I have a browser at home and a browser at work. Both are Mozilla Firebird. I want the bookmarks to be the same in both.

The complication is that I want to be able to add, modify, move and delete bookmarks from either of them and have it show up in the remote. That makes it a bit trickier, but not impossible.

Anyone heard of such a beast? Must run on Linux and Windows (in Cygwin if necessary).