Is it OK to brush my electric guitar neck with oil?

I'd just give it a good cleaning and change the strings like czar suggested. If you want to oil it that's fine as long as it isn't a maple fret board. You can use something like linseed oil on ebony and rosewood.

The fretboard is susceptible to drying out somewhat if you use the wrong type of cleaner on it. The best thing to use is clarinet bore oil. Bore oil is designed to keep ebony clarinets in good condition. Using it on a guitar fretboard is an old luthier's trick. I also suggest changing the strings on it. Guitar strings can get dull even if you do not play them. They are metal, and like all things metal, they will oxidize when exposed to air. Both the strings and the bore oil are available at most music stores.