Ditto the Facebook.... Myspace, ehhh, depends on the area/genre. Most people my band caters to don't use MySpace anymore, but if your demographic is younger/bigger city, it's probably a good idea.
Wherever you promote online, have a very clear, easy-to-find show schedule.
Show flyers have always been a good way to promote, and you don't necessarily need to be a graphic designer to put a good one together (although as a graphic designer, I would say that it can't hurt...) You can always print in three sizes - full 8.5 x 11 page, 2 flyers per page, or 6-8 flyers per page - cut out the smaller sized ones and leave them at the venue a week before your gig.
Make the people want to come to your gig - if you have CDs, advertise that ten people at random will get a copy.
Use local papers and online event calendars to advertise. Lots of times, the online calendars are free.
Get business cards. Carry them ALL THE TIME. You never know when a networking (and therefore, gig) opportunity will arise. (Even AT a gig.)
Simplify all your website addresses. Instead of
www.facebook.com/pages/My-Band-Name/1234567890, use the URL slimmer and just advertise facebook.com/MyBandName. So much easier for your fans to find you.
There are a LOT of internet radio stations out there now that get as much or more airplay than over-the-air radio now. Many of them have independent programming that looks for new, original talent. This is a great way to spread your music to a larger market area.
Use your creativity! Especially with the internet, there's always a new trick to try... And if it gets people talking, they are talking about you and your band.