Formerly known as Foxmarks, Xmarks is a great tool that synchronizes your Favorites/Bookmarks (depending on the browser you use).
Just install the small app on each of the computers you wish to keep synchronized and it does the rest. I really wish I would've found this earlier; years of copying and sorting on numerous computers left my bookmarks a mess.
After one long flight to Chicago I cleaned up most of the redundant and disorganised mess. Once I got back online, Xmarks replicated the changes to its online database and updated my two other computers within minutes of bringing them online.
And did I mention it's free for Windows, Mac and Linux?