Where does 'attahiyaatu lillahi was salawaatu' come from?

Can someone point me to where this comes from? I don't know Arabic so I've had to transliterate: >*attahiyaatu lillahi was salawaat at tayyibaat. as salaamu alan nabee wa rahmatullahi wa barakat. as salaamu alaynaa wa alal ibaad as saaliheen. ashhadu alaa ilaaha il allah washhadu anna mohammed ur rasoolallah*