Implimenting VAT in Tally.

Tally 7.2 and Tally 8.1 are VAT compliant versions. You can generate state specific VAT returns. VAT sales and Purchase annextures can be printed automatically just by entering data in correct format and defining correct ledgers classes. If you have to prepare VAT returns through Tally then company configuration has to be changed.
In case of Tally 7.2 just modify company details and select use for Indian VAT Yes.
In case of Tally 8.1 go to F11 and alter statutory Features in F3. Select VAT to Yes.
Keep in mind to select State from List in Address section. The statutory master would be selected for that state only.

Make separate ledgers for sales and purchase for separate VAT rate. For example if you are dealing in 4% and 12% VAT rate items then you have to make ledgers for Sales 4% and Sales 12% under sales and Purchase 4% and purchase 12% under Purchase account. Correct VAT/Tax Class has to mentioned while creating those ledgers.

Now make ledger for input and output VAT ledgers for collection of sales VAT and Purchase VAT. These should be separate for different VAT rate. i.e. input VAT 4% and input VAT 12% in the same way make ledgers for output VAT for purchase VAT. At this moment you have to assign proper VAT/Tax class for these ledger.
Now make entries by entering vouchers of sales and purchase. and you would find proper figures are appearing in respective forms. You would also find proper VAT computation in VAT computation screen. You can check it by going to Gateway of Tally >Display> Statutory Reports>Vat Classification > VAT Computation

If some forms are not shown then cross check the VAT class allocation for that ledger. Tally has tried to rectified all VAT related problems but still many states VAT returns are facing problems.
For more help regarding VAT knowledge you can see the full white paper available on Tally's site on VAT, or you can find basics of VAT Here.
For any suggestion or your problem related to VAT leave a comment here.