Hello Sudhir,
you can easily centralize your data in an alfresco installation. Mapping the G drivelettter to Alfresco can be the same for everyone, of a different space for different people - as you like it.
The performance access, however, is a tricky part. The bandwith and latency of your connection are the prime factor here and CIFS is a very talkative protocol. You could ease that burden a bit by moving th webdav, but then you face other problems
* only http mapping in WinXP, https is only possible with 3rdparty tools or with Windows Vista
* checkin/checkout is not available via webdav except when using Alfresco share & Microsoft Office 2007 (via sharepoint protocol)
You might be able to solve that by setting up multiple Alfresco instances and start replicating as master-master replicaitons, but how well Alfresoc supports this, I do not know. Would be interesting to know, so if you find out something, post it here please.
The question is - do you really need full simultanious access to all data, or is a big part of data locationspecific or can stand waiting for overnight-replication. If so, you could introduce local Alfresco systems with "mapped share sites" on a central system for teams, who need realtime access. You will have to implement something like that yourself however. Think of it as an siteproxy for "sites" in share, which you could use to integrate remote sites into a local share server.
I hope that helped a bit.
Norgan
Norgan