Well, you are first going to have to open an account at (probably) a discount brokerage firm----there are lots of them around-----Charles Schwab, Fidelity, Waterhouse, etc. Then place an order, however, most firms tend to prefer orders for a certain number of shares, not so many dollars.
I certainly do not know what your financial knowledge and circumstances are, however, if that 1K is most of what you have, I certainly wouldn't suggest that you put it in a single stock. Working for a Company does not necesarily make it good to invest in----as a matter of fact, one could make the argument that if your livelihood is already function of how well the Company performs, possibly you should not put any of your liquid assets in to it. (e. g., Think of all those poor bastards at Enron, Worldcom, Lucent, etc.)
You might want to consider a no load mutual fund---a low cost index fund might be good for you. Start reading----decisions made off of a good knowledge base, with accurate current information and data, are the best ones.