how do I get a 90 day tourist visa for cambodia with an aussie passport in chiang mai??

do I have to go to bkk?

Not worth the trouble, Cambodia makes this totally easy on arrival, just a matter of money, never have to leave the place rest of your life, nor even visit the bureaucrats yourself, dozens of "travel agents" will facilitate for you for a minor fee.

If only Thailand made it so easy. . .

I believe you can only get a 30 day tourist visa, with a maximum 30 day extension after that.

Probably better off to get a 30 day ordinary (previously known as business visa) on arrival and during that 30 days get a 90 day extension, that gives you 120 days and the only extra cost is the $5 on the initial 30 day visa.

As wym says,any travel agent or most Supermarkets will fix the extension for you.

As the last poster says,get a 30 day Ordinary visa on arrival in Cambodia,if flying in,it will cost 25USD,if crossing a land border,they will invariably demand more-up to 1500THB at the notorious Koh Kong border.Once in Cambodia get a 90 day extension,which is added to the initial 30 days,this however,is only single entry / exit.Only 6 and 12 month extensions are multi entry.The cost for a 90 day extension is about 120 USD,it varies from agent to agent.Usually takes 3 working days to obtain the extension

As the last poster says,get a 30 day Ordinary visa on arrival in Cambodia,if flying in,it will cost 25USD,if crossing a land border,they will invariably demand more-up to 1500THB at the notorious Koh Kong border.Once in Cambodia get a 90 day extension,which is added to the initial 30 days,this however,is only single entry / exit.Only 6 and 12 month extensions are multi entry.The cost for a 90 day extension is about 120 USD,it varies from agent to agent.Usually takes 3 working days to obtain the extension

I was able to get a US$25 business visa at the Poipet crossing on Jan 31st with no fuss (and a tourist visa on Jan 20 for the required US$20) - I did have to pay US$2 extra for not having any photos on that second occasion, but that was my fault for forgetting to bring them. I do hear that Koh Kong is notorious for overcharging - I just went in and out there with my 1-year extension so didn't encounter any problems but heard 1200Baht is demanded for a tourist visa and 1500 or 1600 for a business one. Basically, you just have to be nice, a little patient and bargain the price down. No idea if they will budge and give you the visa for the required fee though, but in Poipet they do.