How do I keep cats away?

Hi all - I just moved into a new townhouse and a neighbor's cat is constantly on my deck. I wouldn't mind, except that it's driving my (indoor) cat crazy! My cat won't leave the deck door now... since she saw the cat outside she is obsessed with the cat outside. She just sits there all day and waits for her, and when she sees her she starts meowing and pacing around. I'm also concerned about spraying etc.

Are there any product or ideas that I could use to keep the cat outside away from my deck? There are other cats in the neighbor so I'm also worried about a chain reaction of multiple cats hanging out on my deck trying to get at my cat.

Thanks! - Keith

I"m assuming your cat is spayed. If not, get her done so she won't attract males.

Have a talk with your neighbor and let him/her know their cat is causing problems.

I think you can find som Cat Away spray in the pet stores - check there.