Last I heard the department of lucasarts that was looking into whether or not to make a KOTOR3 was disbanded and the project indefinitely shelved. There have been some faint rumors of a KOTOR MMO by Bioware or just a sequel, but nothing concrete has been published.
I seriously doubt that we will never see another KOTOR, but it will likely be a long time before anything materializes.
If there is a KOTOR 3 from bioware, i would bet it won't come out in the next couple years. Their last big game, Mass Effect, came out on 360 last holiday season. The PC version of mass effect is coming out pretty soon. (it might be out already, I have no idea.) But i would imagine that if they are working on a KOTOR 3, it is still in the early stages. *I could be wrong, and this is complete speculation
According to Massively, Bioware is not, in fact, working on Knights of the Old Republic 3... for sure. After the flurry of rumors (spurred by Kotaku) that they were working on KoTOR 3, everyone assumed that their new MMO had to be something else. Now they've said that either could be true, muddying the waters again.
As you may or may not know, KOTOR 2 was a rushed game. KOTOR 2 was supposed to have 3 acts in it's story, however due to Lucas Art's decision to ship the game for the X-mas holiday season, act 3 of the game was dumped which is why so many people thought the game's storyline was rather choppy and inconsistent.
Act 3 was already in production when the decision to cut the project short was made. Obsidian decided to release the PC version of the game with the unused content. People banded together a few years ago to try to "recreate" act 3 of KOTOR 2. I believe the project had a couple of names, but it has finally settled on:
A KOTOR MMO would get my dollars. As would a KOTOR3 for that matter. Neither has been confirmed though and any speculation currently is just that.
I have been watching the KOTOR2 restoration project over the years. By the looks of things they are close. Hopefully we will see that project completed by years end. There is a droid world that they are not restoring, but another group is working on last I checked.