The TV can detect a 3D signal if the "3D Auto View" option is selected in the Picture Menu. By default that's on. So when the TV detects a 3D signal coming in, it will prompt you at the bottom left hand side of the screen with the Samsung 3D Logo and instructions to power on your glasses. To answer your question directly, it should auto prompt you when 3D signals come in.
If that's not coming up, it's not detecting a 3D signal, and may point back to either that you're not using a v1.3 HDMI cable or higher, or that it's not able to accept the 3D signal.
2D to 3D processes 2D pictures, and can be adjusted so that it's not shallow. You can adjust the depth in the menu settings for that as well, but most people would probably observe that while it's a cool feature, it may not replace native 3D content effects.
I can't speak on the game consoles - maybe someone else has more insight on that, and I hope someone who has some knowledge posts on this. I just can't speak for game console manufacturers, and I don't know offhand if it's a generation issue or something else.
I just hooked up my PN50C8000 3D HDTV and am using a PS3 to run the 3D Media (with the latest firmware update to drive 3D discs installed). I am using an HDMI cable and the powered glasses, of course. I popped in the 3D demo disc (3 Imax 3D movies on a single Bluray disc), selected to play one of the movies in 3D on the disc menu, and the picture didn't change to the typical blurry screen you'd expect with 3D. If I press the '3D' button on the TV remote, it gives me the options of 2D to 3D, the side-by-side option, and the top-over-bottom option. If I press the 2D to 3D option, it does change the screen to a blurred image and the glasses do work but not as well as I'd expect (images appear very shallow).
My question is, if I put in a true 3D Bluray and select 'play in 3D', should the set not require me to press any 3D functions on the TV? I would think that the set would automatically look blurry from the time I started the movie and I could just put on the glasses and turn them 'on'. The manual isn't real clear on this. On a side note, I read on one website that the PS3 firmware update didn't always work with some movies on 'first generation' PS3s. The date of manufacture on my PS3 is October of 2007. I'm not sure if this is a first generation console and if this is the problem.
Can someone with experience with the 3D Samsung sets tell me if either I'm doing something incorrectly or if something appears not to be working properly?