Trying to reach my almost 5 year old.

Try Capture Go on smaller boards first; e.g. 5x5, etc.

http://www.cosumi.net/en/mobile/

I also found connect 6.

I posted about a set of 4x4 puzzles that Inhave played with my daughter: viewtopic.php?f=10&t=13331.

The same company also makes a 7x7 board.

This is where having a tablet PC really comes in handy. Most Android weiqi programs support a wide variety of board sizes. My son (5) started goofing around on 5x5 and is now playing against CrazyStone on Android in 9x9 and enjoying himself immensely. Being able to set different AI levels and numbers of handicap stones means you can eventually get to something challenging but not demoralizing for a kiddie.