My son is five, and I actually trust him with our computer (not a mac, so I cannot recommend 'mac' games.).
However, there are "I Spy" games and others such as "Jumpstart" that work well for this age. If you prefer and don't mind the internet, PBS Kids has a good website, too. Basically, just do a search on home schooling and games and see what you pull up. Your daughter's teacher should also be able to provide you an appropriate list. My son's Kindergarten teacher did.
Just remember to balance her time with some computer time, activity (play time - for moving around so she is not 'stationary' as this can lead to bad habits and health later) time and reading time.
It should all come together for you if you follow a routine.
Oh~ and if you choose to~ 'Click Start' is a great first 'computer' for a little one to have. It helps to develop computer skills and it's a plug/ play on the TV.
EDIT: I love Starfall ~ this helped my son read in less than three days time! :)
Also, I think the reason the teacher would suggest it; it helps with hand-eye coordination and the reading skills.
I personally do not have an issue with my son using the computer or click-start computer as I make it a priority for him to get exercise! He has some time on the computer to play (and decompress), more time reading with us and by himself and gads of time working out with me and dad ~ yoga with me, running on the treadmill or using the stationary bike... he LOVES it!
As long as you balance and monitor your child's sites or games, you truly have nothing to worry about. I find it humorous the way some parents treat this subject. (like the mom w/ triplets. very bizarre to me.)