Yes, you are certainly entitled to talk to anybody you want to if you are just "talking" - or "dating".. It's when you are in a relationship that things get sticky sometimes. Just enjoy your freedom! Even if you get into a relationship and you have guy "friends" -- you are still friends and should maintain that. If your new guy objects - there is something wrong with him. Just be honest - aboveboard - don't hide that you have male friends... You just can't date behind the guy's back. That is cheating. Good luck!
It is definately cheating if you hook up with another person while dating. You are not officially boyfriend/girlfriend when you are in the talking stage.. it's just a way of testing the field and getting to know a little about each other and if you're likely to be a good couple. If you hooked up with someone other than the person you're "talking to" then that won't send a good message to your possible relationship partner and shows disinterest.
No, you are not considered boyfriend/girlfriend when you are just dating. You are really just getting to know each other, and it could go either way. You are not official until you have "the talk" I wouldn't say its cheating if you hook up with someone else, but its definitely not right. Just be safe, use protection. Have fun.