An alternate pilot was released as a bonus episode on the season 1 DVD set. Although similar to the one which aired there are many differences. The narration is done by someone else (not mentioned in credits).

Many scenes are also different or simply cut. For example

-Kyle doesn't walk around town naked in this version.

-Declan doesn't even show up until the party.

-Nicole goes back to destroy Kyle's paper work so she can keep him.

-Kyle doesn't play basketball with Josh.

Also you can see Jean-Luc Bilodeau (Josh) is younger in this version as when it was filmed he hadn't hit puberty yet, so even his voice is higher.

There are also other changes which you'll have to watch the episode to see.

Season 2 DVD Extra

[This is an Extended Version of 01x10.]

The Petersons, Kyle's real parents, arrive to take him home, but Kyle is skeptical about his biological ties, so he turns to Tom Foss for answers. Meanwhile, Steven has trouble accepting that Kyle may be leaving.