What regex can I use to match only letters, numbers, and one space between each word?

Question

How can I create a regex expression that will match only letters and numbers, and one space between each word?

Good Examples:

Answer 1

(?:[a-zA-Z0-9]+[ ])+[a-zA-Z0-9]+

If I understand you correctly the above regex should work. See screenshot below:

screenshot http://img136.imageshack.us/img136/6871/screenshotkiki056.png