With help from people here on the board I obtained a double-entry tourist visa.

It states:

"Good for two journeys to Thailand" The Visa must be utilized before February 15, 2011.

Upon entry in Bkk it is stamped: "Admitted until 06, February, 2011.

I am a bit confused. Must I leave via a border run and return, or simply present this to Immigration in CM and have it stamped (extended) for the x number of days (I'm leaving in the end of February). And does this allow a future return later in the year or do I start the process all over again?

If I just need to have it renewed without a border run where do I go? And the 6th of February is a Saturday, I'm assuming that I can go several days earlier?

This stuff may not be rocket science but I can remember the formula for mono-methyl-hydrazine (rocket fuel) easier than I can remember what to do with these visas ;>

You have the choice of making an exit/return at a border crossing for another 60 day permitted to stay stamp or visiting immigration and paying 1,900 baht for a 30 day extension of stay. Your visa is useless after February 15 so you would not be able to use for another entry later.

You have the choice of making an exit/return at a border crossing for another 60 day permitted to stay stamp or visiting immigration and paying 1,900 baht for a 30 day extension of stay. Your visa is useless after February 15 so you would not be able to use for another entry later.

Thank you.

Since I don't need more than 30 days, I'll pay the 1900 baht. Would someone please tell me where Immigration office (s) is/are in Chiang Mai?

Just before you turn into the airport terminal I believe - between the shopping center and the airport. There is a pinned map in useful information that has them all plotted in Google if you want to check.

Yes, from Airport Plazza drive to the Airport. CM-Immigration is about half way to the Airport, on your left hand.

There is a small sign outside saying "Immigration".