Roth IRA question

I put 5K into a Roth IRA a few months back.  Right now its just sitting in a Ameritrade money market account.  I want to pick 2 funds and split it up. Being a beginner how do I pick a fund without blowing the whole thing?  Do I wait for the market to come back a little?  Thats what my plan was in the first place but it seems to keep going up.  Is it ok to let it just sit in the  MM account for awhile?  I think i should be looking into a no load fund?  Half into a fund that tracks the S&P?  I dont want to be in a situation where i have to watch it everyday and change funds all the time.  I would like to be able to just add to the portfolio every year.    Any suggestions would be greatly appreciated.  Thanks!

Oh, by the way... I'm 36 and am looking to leave the $$ in until im 59 or so...