#2. "Revenge of the Clones" In response to Reply # 1
Just don't buy one of the 'Billingham' or similar cheap Chinese ML-L3 clones. They will open the shutter on a D50 or D70/s in bulb mode, but for some odd reason they won't close it on the second press.
Get a real ML-L3, or a Pogo infrared remote. I have both, but use the Pogo most of the time, as it has an attachment point (I clip mine to a retractable reel), and also has a bit more range. They're about half as much as the ML-L3 on ebay (got mine from seller bearislandtc).
I also have one of the 'wired' infrared remotes from this seller, which is great with the camera on a tripod, or when shooting pole panoramas on a tall monopod. Saved me from having to buy a D70s just for the wired remote...
#3. "RE: Revenge of the Clones" In response to Reply # 2
I've got an original ML-L3 and an "OMG! SR-1".
The OMG! is a compatible remote (compatible with Canon also); it has a built-in LED torch, and it came with a mirrored reflector to attach to the lens (enabling remote release from behind the camera). This unit works perfectly (including "long time" mode) on a D70, so it should also be OK on a D50. Cost: £10 incl P&P from kea-photo on a well known auction site.