Travel to Hong Kong with a "Residence Permit for Foreigner in China"

im a student and just obtained my "Residence Permit for Foreigner", which was pasted into my passport. it doesn't say Visa anywhere, but is valid until 31-jul-2013. next week im traveling to hong kong. does the residence permit allow me multiple entries? does this work like the X? also i'll be moving out of my hotel to live with roommates, do i need to re-register with the police? thank you!!