I live in Canada and am curious as to what differences there are between car seat laws in different countries. Here the law is rear facing until 20 pounds and one year, harnessed forward facing until 40 pounds, and recently a new law passed for booster seat until 4 foot 9, 90 pounds, or 9 years old.

what are laws like in other places?

In the states it varies widely. I'm in WA (obviously :D), and here it is the same - 1 year and 20 lbs for forward facing, 4 years and 40lbs for a non-harnessing booster (so, a belt positioner), and 4'9" (not sure on the weight) before using a seatbelt with no booster.

But these are just guidelines. It's safest to keep your child rearfacing to the max the seat allows, then to keep them in a harnessing booster as long as possible. For a very convincing reason why, please check out http://www.kyledavidmiller.org/ or the youtube video here: http://www.youtube.com/watch?v=azgBhZfcqaQ

warning - you'll need tissues.

Are the car dealerships still doing the child seat safety checks? I am wondering if I can take a friends car down to get some help installing a new one for their little girl.

Yes, I have seen that video before and yes, I needed tissues. My girl is now in a seat that will keep her harnessed till 80lbs in weight, and 53 inches tall (4 foot 5 inches). That means it could take her till she is nine or ten years old, and given that it is a metal framed seat it won't expire as fast as plastic ones. She'll be sick of it, and fight it, I'm sure, but she's staying in that seat until the very last possible day.

Not only car dealerships, but fire stations often offer them too.

I know the dealership we bought our SUV from does them. They have a baby seat with a doll on the coffee table in their sitting area with a sign that says "ask about help with baby" to encourage people to ask for help. Part of the issue I see is when children are tall and lanky. My oldest niece is old enough and tall enough but way below the average weight and thus still not really safe to be out of a child seat. She'd be snapped like a twig in an accident. I never minded mine as a kid, especially as I knew it made me safer.

Your local police station should have a list of clinics and dates for it. I had our seats installed properly at one here. Anything to make our guys safer. What's sad is hopw many people think they're safe when really, they're not.

You should look for clinics hosted by actual certified carseat technicians (Child Passenger Safety or CPS technician). Fire fighters and police are often not actually trained in installing carseats correctly.