You don''t need to own a boat to learn to sail.
The above advice on investigating Sea Scouts and other community sailing programs is very good advice.
Another way to get on a boat is to find a sailboat that needs crew for racing. Not everyone cares if you know how to sail. Often your attitude is more important. People would usually rather have a reliable, interested quick-learning novice who will play on the team than a prima-donna expert that never shows up.
Ask around at the local boatyards and yacht clubs to see if there is a weeknight (or weekend) racing series and if any of the participants are interested in novice crew. Try to find a smaller boat (22-30 foot range) to start with. Make sure the skipper knows your level of sailing knowledge before you get on the boat. Ask for advice on what to wear, where to stow your stuff while on board, and how to do any job you are assigned. Be willing to buy a case of soda or some sandwiches once in a while. Help clean up at the end of the day.
If you end up sitting on the rail for ballast during the race, try to watch the rest of the crew as they work the boat. Talk to the crew members about what is happening once they are on the rail with you.
Once the race is OVER ask questions of the skipper about anything you are concerned about. How to do things, why things happened, what could be done better and how. See if he will explain how to steer while traveling back to the dock.
One risk in taking this approach is getting on a boat where the skipper yells at the crew. Some skippers are ok on land but turn into mean tyrants on the water. Tell the skipper thanks at the end of the day and find another boat to sail on - there will be MANY of them.
Good luck.
--Kevin