Here is a great quick read about good car seats: http://blog.thenatureschild.com/2008/10/booster-seat-warning.html I'll have to investigate when Claire is older when we move her to a booster. Right now she is still rear-facing and can be to 40 lbs in this seat. So we have awhile to go!
Also watch these YouTube clips:
And here's the 2nd one YOU NEED TO SEE IT!