Can I get a good quality 16 x 20 print from a 6.2 megapixel digital camera?

I am trying to decide whether or not to switch from 35mm to digital. The cameral I am looking at is a Nikon D50 with 6.2 megapixels. I have also looked at the D80, which has 10.2 mp. I'm not sure which will be better if I want to get prints larger than an 8 x 10. Naturally the salesman is pushing the more expensive camera, but I just wanted input from someone other than a salesman.

There's two big reasons to get the D80. One is the extra resolution, and the other is the much larger viewfinder. (There's also a bunch of smaller reasons.)
Regarding the resolution, with 16x20 you'll see a difference. You'll start to see a difference with anything larger than 8x10.
Here's why. A high quality printer will be set for 300dpi. That's about as fine as the human eye can resolve. So when you print, ideally you'd have 300x300= 90,000 pixels to work with for every square inch. That works out to a whopping 34.5 mega-pixels for 16x24 inches (from which you'd crop a 16x20 print.)
You only NEED 300dpi if you're going to press your nose to the print, however. If you view an image from a foot or two away, your eye won't resolve anywhere near 300dpi and there's less need to print at that resolution. Even so, there's going to be an appreciable difference between 6 and 10 mega-pixels.
As somebody already stated, 35mm color film only resolves about 8 mega-pixels worth of information. (professional black & white film goes up to 25 mega-pixels). The sensor of the D80 is so good, that it not only out-resolves 35mm color film, it out-resolves most consumer grade lenses!
The Nikon 18-70mm lens ($310) would be a nice starter lens for either the D50 or the D80.

6.2 is plenty enough for 16x20. Now, not EVERY last picture you take will be 16x20 worthy because of fringing and fuzzinessed caused by certain conditions. 10.2 is overkill for the average consumer. In fact, the amount of information gathered by traditional 35mm is closer to 8mp.

Yes you can for fact that I got a 8.5 x 11 out of a 2 mp camera at same time it was from a Panasonic Lumix model.

D50 looks a good camera if its your fist go for it. i work with
digi's and we give a satisfactory guarantee which means if it doesn't suit you, you have 28days to bring back then you can swap for the more expensive. Try and find somewhere like that!! i have a 7mp and that gives fine images. my first camera was a 2mp and that was better than the 4mp so its more about the camera itself than the pixels!!

If you regular take such large prints, then get the D80. Hell, get the D80 anyway. Look. The camera is only about $100 more. And 10 megapixels is a huge jump up from 6 megapixels. You are buying a dSLR camera, for a reason. You want quality. If you were taking pictures on a budget, you would grab one of the higher end digicams for $300-$400. More to the point, you are saying that you plan on taking larger prints, which is the primary reason for getting a higher resolution camera in the first place.