AHK and Keyclone can pretty much do the same thing; however, Keyclone costs $10, and comes not only with alot more features and great support, but is alot easier to work with. I use AHK personally and you pretty much have to manually program every key you want passed on. If you're super cheap and don't mind alot of personal work with no support, AHK's fine; if $10 isn't an issue(or you don't hate paypal like me) go for Keyclone, will make things a ton easier :p

That said, AHK isn't a bad solution, just most people think it's more likely to get banned and requires more work on top of the multiboxing work yer already doing.