A while back I posted a guide on how to automatically sync your addon and config files/directories between multiple machines using live mesh. Since then I've found an alternate way to get the same results using dropbox and symbolic links. By the way, it's a wall of text and this takes a bit of time to setup but if you play at multiple computers you will find the effort well worth it.
Orriginal MMOwned post. See this if using XP or prefer live mesh to dropbox.
Updated method using dropbox and symbolic links:
(Note, this only works in Vista. It will probably work on windows 7 but haven't tried that yet. BTW, If you are using windows 7 and have tried it please reply to this thread and i will rep you.)
Dropbox (https://www.getdropbox.com/) is a service similar to live mesh that many people seem to prefer. Since it will only sync files in the dropbox folder and not the WoW directory we need to create an association between the two locations. This is achieved by placing the files in dropbox and making a symbolic link (pointer - sorta like a shortcut) from the old location to the new.
1. Move your WOW Addons & WTF folders to the "My Dropbox" folder.
For example
move "C:\Program Files\World of Warcraft\Interface\Addons" to "C:\Documents and Settings\User\My Documents\My Dropbox\Addons"
move "C:\Program Files\World of Warcraft\WTF" to "C:\Documents and Settings\User\My Documents\My Dropbox\WTF"
2. Create the symbolic link at the old location.
Open a command prompt and type:
junction "C:\Program Files\World of Warcraft\Interface\Addons" "C:\Documents and Settings\User\My Documents\My Dropbox\Addons"
junction "C:\Program Files\World of Warcraft\WTF" "C:\Documents and Settings\User\My Documents\My Dropbox\WTF"
On the second computer install dropbox, delete your addons and WTF folders, sync your dropbox, follow step 2 above and you are done. Rinse and repeat if you use more than 2 machines to play wow.
If you have trouble with the symbolic links or are using a non windows OS you can find more info here: TipsAndTricks/SyncOtherFolders - Dropbox Wiki
Enjoy only updating addons on one machine and not spending 20-30 min syncing each day.
-Dastin