murfitUK - this sounds like an advanced project to me, multi-site links, RRAS, DC, Readonly-DC, possibly DFS... if you want/need to do this, then first off I'd run through the majority of very good tutorials over at
http://www.itidiots.com. Screencasts, introducing you to 'servers', and all the other things you'll NEED to know, like DNS,DHCP,Domains,RRAS, etc...
My second recommendation is to then sit your MCSE creditation exams, cause you'll be likely upto that standard!, and then jack in your current job and start a new job as an IT Manager... earning big bucks!

....cause what you're asking is demanding, not just to setup and configure but to then maintain (probably the more demanding the troubleshooting side for when things do go wrong!)
....or scrap the idea of the enterprise solution, and install
mesh.com at all sites with one single live account - it's not enterprise and it won't do what you want out of the box, but it's free, dead easy to set up and WILL synchronise document and files accross multi-sites in near-realtime. You can setup a Barabara, Margarat, etc. folders in your Live Mesh desktop and they can all access each others...
I'd recommend the first solution, but get your MCSE first!