I'd just like to know how Rick does housepets!. like, what programs he used, how he makes it so awesomely funny.

having a sense of humor and a hand
arms and eyes are optional, but will improve your work

A flat surface does wonders too.

as does basic motor functions and a working
_____________________________V

Basically, It won't Mather much what you use to draw.
most people use Photoshop.

but you can get the same effect for drawing with free software like:
Gimp
paint.net
and my favoite free drawing software:
Artweaver

Tablets are plentiful, I suggest for a starting person to buy a trust tablet , unless you can find a bamboo somewhere really cheap.
The reason for getting a Trust is that you won't notice the difference that much, only you are a heavy sketch artists (in witch case Bamboo's are more responsive) you might want to spend the extra money.
of course there are more then just those two.