You can use the facility if -
a) You have a bank account with net-banking facility, and
b) Your bank is amongst the banks that provide the e- payment facility.
It is mandatory for the following types of assesses to pay tax online with effect from April 1,2008.
a) All the corporate assesses.
b) All assesses (other than company) to whom provisions of section 44AB of the Income Tax Act, 1961 are applicable.