You can get plants in person at orchid shows, at society meetings, at Lowes or Home Depot, or over the web. Having someone knowledgable help you pick the first plant or two will increase your chance of growing sucess. Because there are so many vendors in so many locations, I have links below to some of my favorites and a rating site for vendors.
My favorite Colorado vendor is Fantasy Orchids in Louisville. In person, on the phone or via e-mail there is a knowledgable staff willing to help you find your hearts desire.
For a good variety of species and hybrids I suggest Oakhill Gardens. Hermann Pigors and his friendly staff are in West Dundee, Illinois.
After hours of reading Ray's comments at RGO, I feel I know him. He has shipped some lovely things to us from First Ray's
If your favorite is a small equitant oncidium, Chula Orchids should be your choice. I have never seen larger clumps of these little jems. Harry Tolen, Supreme Commander and his wife, Patricia Tolen, Supremer Commander, operate this greenhouse and chatty site.
An extensive list of links to Orchid vendors and supply locations is at the Orchid Mall. You will also find links to various informational sources.
The opinions posted at the Orchid Grower Rating Evaluation System, OGRES, are useful, but remember we are all more apt to post a disgruntled comment than a praise. The information available includes a numeric score, the number of people commenting and the web address of this grower.