No, you can't really just go and start sanding frets. Mainly because frets are crowned - which means the tops are rounded and the strings actually only touch a very tiny part of the actual fret. If you were to sand the fret, the string would make too much contact and cause a great deal of buzzing and the notes wouldn't ring out properly. You would also likely mess up the radius of the fretboard.

If you are unable to take the guitar in for repair, you can technically do it yourself (if you are somewhat mechanically inclined). But the tools will cost around $60 to do a decent job. At MINIMUM, you will need a radius sanding block that matches your neck radius and a crowning file (both available from Stew Mac).

So, assuming uneven frets is the problem: the first step would be to tape off the fretboard so only the frets are exposed. Then you want to sand the frets even up and down the fretboard (using a straightedge to check it along the way - by the way, you will have to adjust the truss rod so that the wood part of the fretboard is flat first). Start with around 600 grit sandpaper and work your way up to around 1000. After that, you will want to use a black marker and make a lengthwise mark along each fret - this will be your guide for crowning the frets. File the frets evenly from end to end until there is just a TINY unbroken black line across the length of the fret. Do this on all frets. Then lightly sand the frets with about 1500 grit sandpaper (don't use a sanding block - use your finger with fairly light pressure), followed by 0000 steel wool. Following that, I like to use a Dremel with a buffing pad and metal polish to bring the frets to a mirror shine.

This is all assuming that a high fret is your problem...

Not sure where you are located, but if by chance you are in the Chicago area, I do repair work on the side and will do it for a 12 pack... :D