Tony -
Nikon does have a shutter release cable called the MC-DC1; however, it is only for the D100, D200, D70s and D80 models. The D50 doesn't have an external shutter cable port. Speaking of which, I need to buy one of those before chase season begins; I'm NOT going through another 'press and pray' summer.
To be honest with you, Tony, being a current proud owner of a D70s and having shot with a borrowed D50, I think you'd be much happier with the D70s because it has more manual features, which are very useful in the field, particuarly regarding low light structure/lightning shots. Also the D50 is targeted at the general public, whereas the D70s is targeted at serious amateurs/professionals on a shoestring budget
(you being one of the former, me being one of the latter.

)
One year and
8,000 shots later, my D70s has never given me any problems whatsoever. If you're interested in going the eBay route (which I did), check out Cameta Camera. They're the outfit I purchased my setup from, and I was extremely pleased with my experience. The shipping was fast (left New York four hours after I bought the kit, arrived on our doorstep 6 days later) and the customer service was,
gasp, low pressure, friendly and helpful!
Unlike Ritz/Wolf Camera. I highly don't reccomend trying to buy a camera from them; they put so much pressure on you to 'upgrade' that you feel like you're trapped under a two ton boulder. And their customer service sucks worse than a clogged Hoover.

*end rant*
Anyway, back to Cameta. They are a highly reputable PowerSeller, and have some truly great deals. Right now they have a brand new D70s kit with the body and two lenses,
a 28-80mm and a 70-300 mm, plus some other goodies, for the very low Buy It Now price of $679.95 plus $18 shipping with a little over a day left in the auction. And if you don't want to buy right away, they usually have these type of kits available every two to three days.
Just my $.02, take it for what it's worth, but I think you'd be much happier in the long run by stepping up to the D70s; I know you're on a fairly tight budget, but in my somewhat professional opinion, it's somewhat worth the extra money to get the manual features the D50 lacks. But the true make or break proposition is this:
The D70s has the shutter cable release port.
The D50 doesn't.
If lightning photography really matters to you (and I know it does), go with the D70s. The great lightning shots you'll get will more than make up for the extra $200 or so you spend on the setup. I promise. I almost bought a D50... I'm very glad I didn't. I wouldn't have been able to get half the awesome lightning shots I did last summer if I hadn't had my D70s (and a hairtrigger finger, lol; but that's another story.)