HI Raghu,
I am staying near to Nelson Manikam road in Chennai. I have been using this Aritel corporate Unlimited GPRS for last 5 months and enjoying thouroughly... initially I had some problems in downloading , but after installing "download manager" it is giving a speed of 25 kbps and browsing speed of 200+ kbps. which are quite impressive. I am connecting to my laptop through my Samsung P310 mobile ( EDGE enabled ).
Earlier I used TATA indicom for nearly 1.2 years but had worst experience. was giving download max to 14, and seemingly browsing speed of 230 but not in real.
recenly even Vodafone has also come to our company and started offering unlimited GPRS for only 200 bucks but GPRS ****s... my friends are not even capable of browsing .. Please don't go for Vodafone... coverage is poor and GPRS is worst.
I suggest Airtel ... Airtel is rocking...
Sreedhar