There's a lot of good information over at
http://www.avsforum.com - you should be able to find some good reviews for most of the current popular sets.
If you mention DLP, i assume you are referring to the 'projection' style TV's, not the flat panels.
DLP sets typically have one 'optical' chip in them used to create an image. Light is reflected off this chip to create the image on the screen. The chip is actually an array of miniature mirrors, each mirror in the array = 1 pixel on screen. Each individual mirror oscillates rapidly to vary the amount of light reflected, controlling the brightness of that pixel on the screen. The interesting thing about one chip DLP's is how they create a full color image. If you think about it, just reflecting white light off a mirror will result in a greyscale image. To create color, there is a spinning color wheel in between the light source and the DLP chip. The color wheel sequences through the primary colors, and 1 field of the video image is projected on the screen in only that color. Then another field is displayed for the next primary color, and so on. So if you have a red,blue,green colorwheel, first an entirely red field is displayed, then an entirely blue field, then green. This happens so quickly that your brain/eyes fuse the three seperate color fields into one complete full color image. (No, im not making this up I promise!)
Benefits of DLP are typically considered to be a sharp picture (no convergence issues with just one chip), good color, good contrast and a decent black level. Cons: a small percentage of people see artifacts relating to the way the DLP uses a color wheel to create a full color image. DLP's can also dither the image in some low light scenes.
LCD projection sets typically have three different LCD panels, one for each primary color. A prism splits the light from the light source into the primary colors, each color being shone through a different LCD panel. The three distinct color images are combined to form one full color image on the screen.
LCD cons can be panel misalignment or misconvergence, meaning if the R,G,B panels are not perfectly aligned with one another, the R,G,B pixels on the screen will not completely overap. Also, LCD panels typically do not have as high a fill factor as DLP panels, meaning the gap between the pixels can be more noticeable than DLP. Some LCDs can have an issue with color uniformity across the screen, meaning if you put up a solid color screen, the color may not be even across the screen.
LCD pros - some people think LCD can have more natural or vibrant color than DLP. Also, there are no color wheel artifacts or dithering. LCDs may be a little less expensive as well.
There is another technology you may want to look at called LCOS, or SXRD if you are Sony. This is kind of a cross between LCD and DLP. It has three panels like LCD, but the light is reflected off of them like DLP. No color wheel. Very high fill factor, (better than LCD or DLP) so the picture is very smooth.
If I were looking for a projection TV (not something to hang on the wall), I would look in this order and let my budget decide.
1) SXRD
2) DLP
3) LCD
But thats just me - whats important is how it looks to you.
Oh - just as important as what display technology is in the TV is how good of a scaler/image processor it has. Since all of these TVs are fixed resolution, (the number of pixels on the screen remains constant no matter what you are watching), whatever video source you are watching needs to be scaled to fit the TV's native resolution. This is VERY important when watching regular TV or DVDs when the image needs to be stretched to fill the screen. A TV could have an outstanding picture when watching hi-def, but look like complete crap when watching normal TV or DVDs if it has a bad internal scaler. No matter what you buy, make sure you test it by watching some hi-def, some regular TV, and some DVDs to see how it looks.
Hope this helps, didn't mean to write a freakin encyclopedia

Koz