First off, welcome to the forum, it's good to have you here with us.
To answer your question, I'm not aware of another program similar to TSP. There are several ETFs that track the major indexes, and I myself have used my USAA brokerage account to trade some (low overhead) mutual funds.
Check out our sister site http://www.etftalk.com/forum/ there is lots of good info in there on the ETFs.
Best of luck, let us know which route you take.
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