Can i use the same modem with any hardware modification to make WIFI.
or shall i have to purchase a new modem? which one should i go for?
Yes you do need some extra hardware !!! There are couple of options...
1. Obtaining Type-II / Type-IV modem from BSNL via their upgrade options (avoid this one)
2. Buying a ADSL router / Access point to make the connection wireless...
In first case the Router it self logs in to the Internet via its own PPPoE dialer and your systems both wired of wireless shares the connection from it
In second case, the BSNL modem / Router acts as a bridging device and your 3rd party wireless access point / router (eg lnksys wrt54gl) uses its own PPPoE dialer for looging in and PC / Notebook shares the connection !!!
I vote for the second option as the BSNL are sumpling Nokia Modem / ADSL routers which really are crippled by BSNL restricted firmwares
