I bought FO1 and FO2 a while back, then completed the series and bought FO:Tactics when offered it at a discount. I already owned FO3, but wanted to play through them in order. I was a good bit into FO1 (level 7) when I couldn't fight the urge to jump into FO3.
I've finished FO3, so I installed FO1 and restored my save games. Back when I started, I was using the unofficial 1.3 patch for FO1, but I didn't know that this was the censored UK version without children when I started my game. I'm debating on picking up where I left off since it's been so long, or starting over with the child patch installed. I'm not sure if installing the child patch would cause problems with my old saved game.
I then went ahead and installed FO2, I was just going to start it up and watch the intro video, but then I created a character and started playing. A couple of hours later I had to force myself to quit before I spoiled too much. I was surprised when I got to the first town and saw children running around and realized that it was the uncensored US version.
So why is version of FO1 sold here the censored version, but FO2 isn't?

I was surprised about that as well.
I think it has to do with the thieving children in The Den.
If you install the Fallout 2 Restoration Pack you can get a quest from Mom to house the children in an orphanage.
That way they're taking care of and don't have to steal.
As for FO1, simply install it.
Than copy the game directory to another directory.
Afterwards install the patch in the original directory and check to see if your save game still works.
If not, remove the directory and rename the copy.
If so, remove the copy.

I've already tried the child patch on FO1 with my save. I can load my save game and see kids running around, I just don't know if I'll run into problems later on by playing 1/3 of the game without it.

You don't miss anything.
According to [url=http://user.tninet.se/~jyg699a/fallout.html]Per Jorner's guide[/url] all you miss out on is the chance of stealing a BB gun from a kid in Shady Sands.
If you finished 1/3 of the game, you should have no need for that.

You should not as they are not actually disabled, just invisible and they will still pickpocket you but you can't do nothing about it except buy anything they steal back from the guy they take the stuff to.

That only concerns the kids in The Den in FO2.
I've never experienced pick pocketing kids in FO1.

Oh right, got the two games mixed up :P Been too long since I last played.

Yeah, but nothing gave me more satisfaction than figuring out I can actually enter combat mode to go past the steeling kids so they won't have the chance. :) Same with the Gecko power plant, reaching the map exit in one turn without the stupid guards initiating a conversation and not letting me in.
On that note, I think I read it somewhere that in FO2 childless versions you can still become a child killer if you manage to accidentally kill an invisible one with splash damage weapons like a rocket launcher. Can anyone confirm that?

I do know in the censored version you can still become a child killer by killing a family of farmers as you wander the world map. The child uses the same male model as other townsfolk/farmers but if you hover the mouse over him he is described as a child.
Kill him, get the tag and karma hit and ready yourself for lots of bounty hunter random encounters on the world map.