Dubey:
YOUR QUOTE:
<DOES THIS MEAN i do not need to treat F1 and H1B differently for year 2005 and can file as if i was on F1 for the entire year using the calculations i did in year 2004 also? If yes then do i need to fill out any other form with this?> Yes, this means you file as a non-resident alien (filing Form 1040NR or 1040NR-EZ for the entire year.
Since you intend to return to the U.S., you should plan on filing.
I have no links for you to use for calculating your taxes. The only software that I know of for non-resident alin filing is
www.cintax.us, which does NOT do F-1 to H-1 conversions well at all. You probably need to do the tax return manually this year.
Assuming you have either an ITIN or SSN, you can file Form 4868 ONLINE at
www.irs.gov. If you owe money, you need to mail a check by April 17, 2006, as the extension is an extension to file, NOT an extension to pay. If you know you will get a refund, then just file the Form 4868.