Here's what we sent (taken from my cover letter):

• Complete Form I-751 - Petition to Remove Conditions on Residence
• Filing Fee of $275 (via personal check) payable to U.S. Department of Homeland Security.
• Photocopy of Permanent Resident Card (showing both front and back)

Evidence

• A copy of the lease agreement for our current residential address in New Jersey, containing both of our signatures.
• A copy of a bank statement for our current checking account, showing both of our names.
• A printout of the confirmation page from the website for my 401K, showing my wife as the primary beneficiary.
• A copy of my current medical card from United Healthcare, showing both of our names.
• A copy of the payment agreement for our car, signed by my wife and I.
• A copy of our 2005 Joint Income Tax Returns.
• Copies of airplane travel itineraries for a trip to Los Angeles between in October 2006, with myself and my wife listed as passengers.
• A selection of printed and digital photographs taken between October 31st, 2004 and February 1st, 2007.
• Signed letters from friends and family members testifying to the authenticity of our marriage.

sounds good to me..!! good luck!!

ohh btw can we send a money order too for the fee or do we need a personal check?

I can't remember offhand what the instructions said for forms of payment - except to (obviously) not mail cash. Personally I would (and did) send a check. At least that way in the extremely rare instance that the package gets lost or the payment somehow detached from the rest of the papers you can cancel it relatively easily and send a replacement. With the money order your money is already spent, and it's a hassle (to say the least) to cancel and reverse it.

That's the problem we have with our current landlady - she insists on being paid by MO, which is expensive and inconvenient.

Looks like the fee check was cashed today!