Calculating tax as a web professional

Hi Guys,

I am a web based professional. I work primarily with website development and take on custom programming projects from clients located in the US, UK and AUS.

In the past year I have received payments from clients in my personal bank account. 

As a professional, I have expenses as well for these (Software/Script Licenses, Web Hosting/Servers, Third Party Service Payments etc.) which are bourne usually through my debit card.

This is my first year paying my income taxes, so can you tell me as to how am I supposed to calculate my taxable income. What form should I consider in e-filing etc.

Any guidance would be greatly appreciated.

Abhi