Need: Folder Sync tool

[Christy]

I have a PC at home, and laptop at a diff place. Certain folders need to be synced( with the newest version of the file in the folder). But both computers never come online together. + the Syncing must be differential or incremental( ie, only modified files should be synced), coz the internet connection on one of the systems is not very good in terms of bandwidth.
Platform Win XP.(both s/m)
Total data in folders: 500mb max
Any solutions?

[Raymond]

If both the computers never come online together, where do you save the changes? In an external drive?

[Christy]

I think most people already know about the app, but i just used it for the first time now.
Settled for Dropbox:http://www.dropbox.com/. 1 account, clients on both machines.
Free space -2GB.

Just put the entire working folder into Dropbox. The site says it can sync across PC,Mac,Linux and mobiles-android,iphone,blackberry.

It went so well , & when my friend wanted to sync his entire My documents, changed the location of My Documents to Dropbox folder, now both his PCs MyDocs are synced.