I have been a VSNL dial-up user for the last two years and am glad to report no complaints. They have this 100 hour dial up TCP/IP plan (Plan 100) that is valid for three years. The best part of this plan is that internet access between 11 pm and 8 am is free and so is access on Sundays.
If you plan it well, you could stretch the 100 hour connection across 3 years ! Connection is immediate and there have been very few occasions when the connection has been lost. A mail account is also provided with 5 MB mailbox for Plan 100 and above.
The application process is very simple, especially if you can go to their office. You fill up a form with basic details, pay Rs. 788 and receive the Installation CD. The CD also contains useful software like the 2 browser software - IE and Netscape (latest versions), Anti-virus Software (evaluation copies), Evaluation copy of iLeap - the Indian language Wordprocessor, etc. apart from the registration software and the dialer. Roaming access is provided at an additional fee. If you cannot go to their office, you could ask one of their resellers / agents to meet you. online.vsnl.com is the Website that provides all the info for New Registrations / Renewals in one place.
Have also tried Dishnet and Satyam for some time, but found VSNL the most reliable. Their free service at night and on Sundays makes the Plan 100 very economical. Go for a VSNL connection today !