The easiest way to get an fMRI (and many other brain) scan is to volunteer to be a participant at your local university, hospital, or research center. They will let you keep a picture of your brain, provide some interesting information at de-briefing, and usually even give a bit of monetary compensation for your time. Since the research group has to have an MD on board in order to do these tests, they will also notify you if they detect something abnormal or dangerous in your scan. The only caveat is that the selection criteria for being a participant are usually a little bit more involved than in a standard psychological study. Thus, you might have to volunteer for a few studies before you are selected.
If you want further analysis, you might consider companies like this. There you can submit your brainscans after you've received them for further analysis.