The following pages describe many places to stay in areas described. They are all places of which I have first hand knowledge. A further handy reference is the Western Australia Accommodation and Tours Listing page, that has an easily browsable and searchable index and details of hundreds of places to stay. They also have some great maps that show the locations and places to visit.
he Yellow Pages provides a comprehensive reference for places to stay in Perth. There are a lot of choices. Four possibilities are listed here.
If you fly in, and require a place to stay overnight while arranging you car, roof racks etc, you can stay at the Bel-Eyre Motel. This motel is close to the airport, and has a courtesy bus that will pick you up from the airport. The bus is big enough to take sailing gear. Contact details are here.
If you want a really great place to stay you can try the Quest Harbour Village Apartments. It is a little more expensive than some (most), but is quite superb. The Harbour village is in the middle of the exciting area of Fremantle. This is a vibrant and exciting area of Perth, that hosted the America's cup one year.
The harbour area is fascinating, and at night there are dozens of restaurants and places to go, all in walking distance of the Harbour Village. This place is worth the stay. Contact details are here.
It should be said that the serious windsurfer / kitesurfer proabaly won't want to stay in or around Perth for long, but will travel up and down the coast to the spots outlined on this web page.
That being said, there is some good kiting in and around Scarborough / Cotesloe, and for beginners (both windurfing and kitesurfing) the river can provide some alternatives.