Even us guys with hair have that problem ;-)
Some ideas:
1. Sweat-Gutr: this is a little clear plastic headband that catches the sweat like a rain gutter and diverts it to the sides, behind your eyes. I've ridden at least two summers, including two Hotter 'n Hell Hundreds with one of these, and it works pretty well.
2. Headband: I've got one of those CoolMax headbands with a little rubber band on the lower inside surface that does about the same thing. It works well, but since it's a lot wider than the SweatGutr, it tends to get up under the helmet and make me think there's some sort of compression band around my head.
3. Do-Rags. I'm a little bit challenged too, when it comes to tying these things on, so I don't try this very often. (Guess I wouldn't make a good pirate or motorcycle gang member). It does have the advantage, if you're hairless, of blocking the sun that comes in through the helmet vent holes and making you look like that Darth Maul feller from the Star Wars movie...
4. Cycling cap, worn under the helmet. I like this one, especially when the sun is low and in your eyes, or when it's raining... the bill of the cap gives you a little more shade...
Tom