let's take it back to the concrete streets.
yup, look at the framebuffer howto for details of what settings to use. that's is assuming you're on an fb (you get a tux logo on the screen on boot, or similar) if yuo're not you can still alter the text size, but not the resolution, which leaves it looking very 'sucky' indeed. basically tho, you'll be setting a 'vga=xxx' value in lilo.conmf, and then running 'lilo' to actvate the changes.
be careful not to attempt to use a frambuffer if you aren't already tho as it might mess your screen up a bit. (only temporarily tho)