hey aryan boy, here's what you'll need
1) a cd driver to install the modem. (probably available on the bundled CD you got with the mobile phone)
2) a data cable to connect your mobile to your computer.
3) you'll need to activate airtel gprs MO on to your mobile phone by sending GPRSACT to 222
you'll get a confirmation sms within a minute or two.
now make a connection on your computer
start > programs > accessories > communications > new connections wizard
connect to the internet > setup my connection manually > connect using a dialup modem > enter isp name > blank username > blank password > *99***# will be the no to connect > next next finish
entering settings
start > settings > control panel > phone and modem options > select your modem > properties > advanced > extra initialization commands > enter this line below...
+CGDCONT=1,\"IP\",\"airtelgprs.com\"
done!!! now try connecting...
billing is Rs. 15 a day in mumbai... not sure elsewhere.
Thanks rageaddict for explaining these complex stuff in a simple way..I will try.. and get back to you if found any prob!