This will be my 6th year of filing taxes; I filed my first US tax return in 2004. So I know I'm supposed to be using Form 1040 instead of 1040NR. I was also self-employed as a contractor in 2009, as I was in 2008, while being in OPT for both years. I didn't pay any self-employment tax in 2008, but then again I used 1040NR then. Do I have to pay self-employment tax for 2009 because I'm using 1040 this year?

After 5 years on F-1, you will file resident tax return and pay SE tax at 15.3% of self employed income. Your U.S. Tax Return: Tax Filing by Self Employed Sole Proprietor or Independent Contractor (http://taxipay.blogspot.com/2008/04/tax-filing-by-self-employed-sole.html)

Thanks for your response! I was hoping I wouldn't have to, since I was still on my F-1 visa while I was working as a contractor and hadn't completed 5 years in F-1 until September 2009, which is when my contract position also ended and I started regular full-time under H-1B the following month.

Sorry, but your H-1B visa undercuts any argument for closer connection to home country, so the contract pay IS subject to the 15.3% self-employment tax.