Car seat safety recommendations seem to be something that are constantly changing. Lately, they seem to be changing for the better, particularly with the AAP's recent recommendation to keep children rear-facing until age two.
The following is a crash test video from Sweden showing child sized dummies who are forward facing and rear facing. Note the amount of impact that the forward facing child has to absorb.
Something that I notice a lot when I see people putting children into seats is straps that are too loose or chest clips that are all the way down at the crotch or belly. Straps need to be tightened and chest clips are called "chest" clips because they need to be placed between the child's nipples.
One good resource for parents is the Family Safety forum at the Mothering message boards:
Another place to get car seat safety information is:
You can see if your car seat has been recalled here: