There are at least two variations to this scam:
1. The check is phony, but the bank does not notify you until after you shipped the item.
2. The check is written for more than the asking amount. You are instructed to send a MoneyGram for the difference. In this variation, the scammer does not care about the item. All they want is to get the MoneyGram before you learn the check bounced.

So, instead of cashing the check, file a Mail Fraud Complaint!

Short warning from the Craigslist site:
DEAL LOCALLY WITH FOLKS YOU CAN MEET IN PERSON!
follow this one rule and avoid 99% of scam attempts.

I just received an email on Craigslist from this guy. I'm selling a pool table also. I live in Pa. What was the outcome of your situation?

I exchanged several text messages with a man who called himself Rick Curtis. I'm selling my pool table on Craigslist and he demanded my address so he could send me a cashiers check. He said as soon as I had it cashed, he said he would send his "agents" to pick up the table from my home as he was residing in the midwest. Seemed very shady so I gave him a P.O. Box address instead. My boyfriend spoke to him on the phone and couldn't figure out if he was a thug or a foreigner. Definitely didn't have a good vibe from the situation. SMH.

This cat is a Craigslist scammer.... wan't to buy your "item" send you a paypal and have you wire him money back for shipping..... only the paypal is bogus.