Just figured it would be useful for someone who wants dialup in Delhi
Option 1. MTNL post paid CLI Based Dialup http://delhi.mtnl.net.in/services/internet.htm
This one is free and can be accessed by dialing 172231 with id and password as the customer’s phone number without the code
Option 2. VSNL prepaid dialup (TATA Indicom) http://www.internet.vsnl.in/index.html
This is one is comparitively reliable and sometimes I use it as a fallback. You need to dial 172226 and use your id and password. You can register that at the link above. You will need to buy a registration pack and could simply follow the installation instructions at the back. For some reason the installation cd complained about unwanted levels of noise in the phone line.
In any case dialup access seems to be getting worse and worse with speeds getting slower and disconnecting often. There are many other options for dialup but i find these to be cheap and easily available.