Domestic partners buying a house? Accountants welcome.

Here’s our situation:

I just bought a house with my girlfriend/partner of 9+ years. We live in California. We want to maximize our tax advantages and save as much money as possible.

Our plan was to get married in June 2003 on our 10-year anniversary. But would it make sense to get married in 2002 just for tax purposes? When she files, she does deductions and the whole nine yards. I turn in my 1040EZ. Can we both get a tax break in 2002 even though our finances aren’t officially merged? Does it make a difference when we’re married in the year 2003?

Our paperwork isn’t filed yet and we’re open to a quick trip to City Hall if necessary. Anybody knows what makes the most financial sense? I can clarify if this is murky or more information is needed. Thank for any help.