Whats VAT Input Credit

Narayanasamy.Y (Freelancer-Accounts&Tax)   (92 Points)

10 May 2007  
Hi Friends
         Can any one tell me whats VAT input credit in brief

Which Inputs can be considred for this calculation ,ie rate wise purchase with similar tax rate sales,Interstate claim is possible or VAT credit can be calculated only between intrastate Purchases and Sales?

Regards
Narayanan