Pre book Ko Phi Phi late Jan/Feb 2012?

My husband and I are going backpacking in Thailand for a month, this Jan/Feb 2012.
We're on a budget and easy going, just wondering if in places like Phi Phi or Phuket you should pre book a hostel, or if we can hop off the dock and find low budget hostels easily?
Thanks

Late Jan/Feb should be no need to book in advance.

Don't be afraid of using touts on the ferry or pier - they can show you pix and haggle on prices. Got a fair bit of info and pix on Phi Phi HERE might help your planning.

i noticed that many thai hotels offer much higher rates if you prebook on internet, then when just showing up?of course you risk that ceratin place is full... is that the same fot phi phi?

Quite often the hotel's own website and rack rates on display in reception are higher than you can negotiate. But this depends a lot on vacancy rates - it can go the other way (you end up paying more than the website rate) when things are really busy.

What I have noticed is that often the big booking sites like Agoda and sawadee.com can negotiate better rates than I could ever manage - once again vancancy is important - more likely to be shoulder and low season. But it can happen at other times - always worth checking them. Their user reviews can be helpful too if you realise than some people are impossible to please.