Want to migrate to Linux Platform

We are using the following applications in Microsoft Environment. We would like to now migrate to Linux Platform so that we can save on  exhorbidant Microsoft Licensing fees. Can it be achieved? Let me know how to go about it.
 
1>Novell Server which runs our foxpro based application in DOS mode.
2>software in VB backend  MS-Access
3>POD scanning software in .NET backend SQL server
4>Attendance Software backend  MS Access
5>Quick heal antivirus
6>Normal office related work in Word, Excel, Powerpoint etc.
7>Tally 7.3 multiuser (Accounting s/w)
8>Mdaemon Mail distribution server
9>Wingate internet proxy server + client

How feasible & reliable would it be to migrate to Linux. Valuable inputs would be highly appreciated.

Thanks & Regards,
Pavan Bhandari