On your Mac, launch Messages app, then -> Preferences -> Accounts.
Make sure an account for your Apple ID exists and is enabled, otherwise add it.
Under the addresses which you can be reached under, your iPhone's phone number should show up, and you should check the box to select it, too.
It then might make best sense to "start new conversations" from that number as well to not confuse people with multiple conversations started due to you using different sender numbers or email addresses.
Your iPhone and the Messages app on the Mac need to be using the same Apple ID.
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously