"If these folders are on the same computer, then you can create a single folder and a symbolic link to that folder, known as a junction on Windows. This way you don't need to synchronise at all: the two folders are actually one single folder with two names, and hence are in-sync by definition. (Note that Windows does not support junctions to directories on remote shares.)
Or, if these directories are on two (or more) different computers, or maybe even different operating systems, maybe sign up for Dropbox? It's free for 2GB (up to 3GB with referrals). This will synchronise automatically, and also give you all other nice Dropbox features such as backup, revision history, online access and file sharing.
Dropbox recognises if computers are in the same network, for super fast transfer using LAN Sync, but even that requires an internet connection while (automatically) synchronising. And the folders you want to synchronise should reside within the Dropbox folder (which itself you can locate anywhere you want)."
