I have two little kids. By little I mean 2 and 4. My wife bought a Wii because some of her friends kids enjoy playing it..so far its been a bit of a hard sell for my kids (on the upside they seem to enjoy watching ME play..which is fine by me). 
 
Can anyone recommend any games to me for that age range? It came with Wii Sports (they like a few of those games) and we bought the Winter Olympics game (too much for them) and Resident Evil 4 (I might be a bastard, but I'm not letting my 4 year old shoot zombies...call CPS if you must). I rented Cars because my son is a total nut for the movie, but it really wasn't all that kid friendly of a game imo. I'm looking for simple, easy to play but fun games.

That is a hard age group to appease, due to limited, or not reading skills.  You may want to think about Wii Sports Resort as it has more games than the first.  Wii Play has some simple games to play and it gets you another Wiimote.  I do implore you note to waste money on any of the cheap games that are marketed to kids as they are truly bad.  That includes all the mini-game collections.  Ensure you check with metacritic.com  (   alphabetical order  )  to see what they review like before wasting money. 
 
Super Smash Bros and Mario Kart shouldn't be all that hard for them to play and you will have fun as well.  Mario Party could be fun as a family game.  Raving Rabbids games can be fun, but actually really hard with some.  Punch Out ?  MySims, especially if one is a girl, but again, can be difficult to navigate.  Endless Ocean may be nice.  Elebits is a simple shooter in a cute and excellent way, or even Dewy's Adventure, which is simple and nice.  Possibly Animal Crossing. 
 
They will grow into the games, especially your 4 year old so don't be tempted to dumb down to much. 
 
If you really want to teach them stuff, get House of Dead: Overkill.  It is motherfucking awesome  :-)

" Bonsai Barber (wiiware) should be quite some fun for your kids. "

Get NSMB.
 
I think young kids have a harder time getting into video games because they're so complex now a days. Show him some good old 2-D mario platformer goodness.