I ordered a replacement lamp for my Mitsubishi DLP TV last week from projectorlampsusa (see link below). I checked around and they appear legit. I soon will find out. What amazed me is that the after-market lamp I purchased costs $149.99, while a replacement lamp purchased from Mitsubishi is $229.00. Not as much price difference as I thought there would be.
Just be careful of aftermarket bulbs. I have seen a lot of customers go after a less expensive bulb and save some money up front but be snake biten a few months later when the bulb goes out. Most of these guys have a 30-90 day warranty on the bulb. Also some of these lesser expensive ones are for just the bulb and no housing. I have no problem with switching the bulb out of the housing but for some they may not want to mess with it.
I had a very bad experince with aftermarket bulbs for my Samsung. I now use either Samsung or Philips. The Philips bulb seems to last the longest although I probably do not have a large enough sample to accurately compare.
I also replaced the color wheel last year which was shockingly easy once I figured out the internet instructions.
I just replaced my lamp on monday. My samsung is almost 2 yrs old and this was the 1st time I've had to do anything to it. I got my lamp from www.advancedlamps.com and I'm happy with it. $116 shipping including. It came with the housing, so I just plugged it in and it was golden.