There are no tax consequences to gifts given between spouses (you are essentially giving your spouse half the house). This will not affect your income taxes now, and will not affect the capital gains position if and when you sell. (You will still be allowed a $500,000 capital gains exclusion if you file jointly, since marriage imparts ownership for tax purposes.)
For all other questions, consult an attorney. @Anonymous_ guesses at some of the reasons you might want to do this, but you may have a different reason, and you could find yourself in a bad position if you don't have this reviewed by a legal professional who understands what you want to do but also why.
