I think you mean ING’s Sharebuilder program.
This is set up to take advantage of dollar cost averaging strategy. The idea is that you set up an account with automatic stock buy orders on a regular basis (once a week). The amount spent each week is the same (it should be an amount that is safely discretionary out of your net pay), but the share price will vary. When the price is high you will buy fewer shares and when it is low you will buy more shares.
Dollar cost averaging is a very good strategy to be aware of, but if you are just “testing the waters” I don’t think blindly signing on to ING’s program is a good idea. You should probably learn something about the stock market and investing first. Investing in mutual funds before going into individual stocks is also an excellent “feet wetter”.
If and when you do decide that you are ready to trade stocks individually, know your investment strategy beforehand (i.e. what you plan on doing with the money when your brokerage account is all set to go). Then practice that strategy on paper for a few months (6 months is a good amount of time) first, to see how well it plays out and how well you understand what you are getting into. Many brokerage companies offer a “virtual” trading account for free, as a service so that your “paper trading” is easy, quick, and completely realistic.