How to sync bookmarks across Google Chrome and Mozilla Firefox bookmarks?

Yes, as jcnaquin suggested, Xmarks is awesome.

(Chrome Extension, Firefox Ad-on)

Not only can you do cross-browser, but you can set up profiles for different computers (Work/Home/Custom) and determine which bookmarks/folders go with each profile. This can help you choose if you want specific bookmarks to be at home, or if you want to leave them at work.

In addition, you can sync Passwords, or Open Tabs on each computer, but only if you want to, of course.

Give Xmarks a try.

There has been a tentative project to implement Weave Sync into Google Chrome

as well as