whoa-- slow down cowboy, you can't just go and buy a d300 and shoot weddings- it don't work that way. Your going to need a few years of experience and at least 10 grand more in equipment, probably a lot more of both.
For starters you'll need another camera- nobody especially the brides mother would let you shoot their wedding with just one camera-- if your camera breaks the wedding would be ruined. Another thing, your wimpy little D300 doesn't have the power, you need at least a full frame sensor which your camera lacks, and it don't matter anyway, you'll need a medium format not 35 mill. and then the lighting, you'll need more than the type that attaches to the hot shoe.
Goog god, get a education there my friend before making such outrageous statements