A resistive touchscreen is the type that was used on the Palm Pilot and many older phones as well as most GPS navigation systems. It reacts to pressure. Some of them are tuned to only react to high pressure, and require a plastic stylus or a fingernail. Some are tuned to react to human fingers, but still require a firm press on the screen, not just a light touch. Resistive touchscreens usually don't have multi-touch capability (i.e. two-finger gestures), but I understand some do.
A capacitive touchscreen is the type used on most modern smartphones. It senses electrical contact with the skin, so it only requires a very light touch. But it does not sense other objects (e.g. a plain plastic stylus - though there are styluses that are specifically designed to be sensed by capacitive screens.)
There's a third type of sensor called "active" or "electromagnetic" - it only reacts to a specially designed stylus, but has very high resolution, and also has pressure sensitivity. Wacom and Ntrig are the two leading manufacturers. Some tablets combine this with a capacitive touchscreen - e.g. the HTC Flyer and Jetstream, and the Lenovo Thinkpad Tablet. (Also most high-end Windows tablets have this.)
As for the display type, see here
. Basically, TN is the type used on most laptops and computer displays. They have narrower view angle than more advanced types (IPS, PVA and similar). View angle is a more important concern on handheld devices - you want to hold it at any angle you want (e.g. whatever is most comfortable to type on) and still be able to see the screen clearly. If you tilt the display and the color and contrast gets noticeably worse, it's probably a TN screen. If you can lay the tablet flat on the desk/table, sit back in a chair and still read the screen clearly, it's probably IPS or similar.