apps from the app store are tied to your Apple ID. you can re-download them free of charge from any Mac as long as you're logging in with the Apple ID you purchased them with.
TM will also take care of this unless you exclude your applications folder from backups.
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)
Thanks for the replies. I thought it was similar to iTunes where you can only download music once etc.
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)
Thanks for the replies. I thought it was similar to iTunes where you can only download music once etc.