psst. because i didn't see it explicitly said in the other comments, i'ma throw this in just in case -- and, as far as i know, this is the same on both sides of the us/canada divide.

undergrads usually take five classes a semester. most schools will let you take up to seven, but everyone i know who has taken more than six has had to do a little bit of wheedling to get the last class. most schools will also count three or four courses a semester as a full course load. it just takes longer if you do it that way. some us schools are on a semester system, and some do quaters (i think that's what they're called, at least). your average undergrad degree is 20 credits, but some schools offer a 15 credit programme. (er, i guess they would say 'program'.)

if you want to go into law right away, liek graduate and boom, welcome to law school, you need to get your lsats done early in your fourth year. people make a big deal about them, and you can take prep courses and mockups and stuff, but, judging from an old one my roommate was studying from, they're not that hard. mostly a lot of problem solving questions. "if tom and jenny have five zebras each, and tom has two zebras with blue stripes and one zebra with red stripes lalalala how many oranges do the orang-utans eat each day?" sort of thing.