It can be very professor-dependant. I had a couple bad professors who made it into really dull reviewing of the reading material. Most, though, had very interesting and interactive lectures and guided discussions where everyone (except me) would debate the issues. Though I was afraid to talk, it was always fun to come to class to listen and then take my ideas home to write online.
As far as content goes, an intro class will probably outline metaphysics (ex: what's the relationship between mind and body?), epistemology (ex: how do we know things?) and ethics (ex: what system can tell us whether an action is right or wrong?) and force you to read Descartes, who was an idiot but whose many flagrant mistakes were instructive and launched modern philosophy.
The great thing about philosophy is you can get an A by lightly skimming half the assigned reading as long as you're paying attention in class and can write and argue well.
I flunked out of the computer science major working ten times as hard as I did getting near-perfect grades in philosophy after.
