I have a '99 Dakota 5.2 that I obtained used and it came with a 10" Edelbrock Round Air Cleaner. I'm a newb when it comes to cars and trucks so I don't know if it's doing damage to the engine by letting dirt in or not. Anyone have experience with this brand? Where may I find the stock intake manifold for this truck? Thanks, guys!

 

I got the same intake a month or two ago. It flows way more air than the stock air box and is a cheap alternative to a "cold" air intake. About the dirt, as long as you have a good filter it will keep all the dirt out of the engine. I used the paper filter for a week but bought a K&N 10x3 instead because it felt like it wasn't getting enough air in the upper RPMs. I don't want to post large pictures here but check out my photobucket account:
http://photobucket.com/albums/a252/novaDAK/

I was originally going to get a 14x3 air cleaner but I cant see how other people manage to fit one in the Gen III (or Gen II on this website (1997-2004)) engine compartment without it hitting the radiator hose or firewall. Anyways, the Edelbrock is the best choice because it has the hookup for the cranckcase breather hose on the bottom to keep you all legal if they do the visual inspection in your state. The Edelbrock says it is a 10" but it is just a bit smaller, so true 10" filters will be a tight fit. I bought a K&N that was something like 9.6"x2.8" or something. It fits under the hood and doesn't have clearance problems. Just close the hood slowly to check clearance for the wingnut.
The intake manifold is the gray metal thing below the throttle body which is below the stock air hat or air cleaner. The stock manifold has the firing order stamped on the top front so that should help you spot it.

 

By rereading your post, It came WITH the air cleaner, when you said where could you find the stock intake manifold, did you mean the stock air intake so you could replace the Edelbrock air cleaner with the stock setup? If so, you could check junkyards, or maybe people here that have replaced their stock one with a "cold" air intake may want to sell theirs, or, as a last resort (probably most $$) go to the dealer and get a new one.
Mine came missing a part of the stock setup (part that goes from the filter box to the fender) so I figured I'd replace the whole thing instead of locating the missing part to buy.