I'm planning to take my two children (9&10) to Port Douglas for 10 days next autumn and was wondering if anyone had any tips for places to stay, good ways to visit the reef /get good snorkelling experience and other things to do.

I was on holiday in Far North Queensland a few weeks ago, although I stayed in Cairns.
I can recommend a trip to Green Island. It is right on the gorgeous reef and there is good snorkelling to be had there as well as a trips in a glass bottomed boat.
The Daintree Rainforest is close to Port Douglas and well worth a visit.
The whole area is a lovely part of Australia

We were there in July - great place.

We stayed at Central Plaza apartments - would recommend.

Didn't snorkel as out littl'un is too little.

We stayed at the Rydges resort which is a nice place to stay with good facilities at a resonable rate. Also it's right accross the road from the Mirage. We spent quite afew days by the pool at the Mirage and were happy to use their facilities too. We were asked for a room number when buying drinks etc but just paid cash for everything and avoided the question. Nobody seemed to mind. 5 star holiday at 3 star prices )

I stayed here last time i went:

http://www.tropicalnites.com.au/

Got a great 3 bed villa for pretty cheap!

Do not stay at the Sheraton Mirage. Was once the jewel in the crown of PD but now run down and badly run. We stayed at a hotel recently for adults only so no use to you but I do have details of a great holiday let if you are interested?

We went up to PD at Easter this year and stayed here. You are right, it is run down and decor is very dated, all peach and turquoise.

I love it up there, we liked Palm Cove and might like to base ourselves there if we visited again. With maybe a night or two up on Cape Trib.

We did our reef trip with a company called Poseiden and they were excellent, I will definitely be using them again.