I haven't played 4E yet, but I heard it was pretty bad and 3.5e is still the way to go and the most played one now a days. Currently I got a group of 8 going, my brother is the DM and we're having a blast. I'd personally recommend 3.5 edition, as the changes I read about in 4e don't seem desirable to me.
We also made ourselves an ultimate DnD playing board for a low cost and I'll tell you how to make one.
What we did was buy a white dry erase board (we got a big one, like 2 feet by 4 feet, but any size will work though the bigger the better). And take a straight edge and drew out an entire grid with the dry erase markers so the whole thing is one giant grid. Then we took a razor blade (a knife will work) and carved little + marks at every intersection in the grid. then when that is done, erase all the markers, and you got a whole bunch of + signs covering the board in a perfect grid. With these, you can now use dry erase markers and draw up maps on the fly. We got black ones for making the map, but also red markers for like throwing in fire that's spreading and whatnot or blue ones to signify bodies of water on the map.
So if like your group of adventurers is in a dungeon, and all they can see is a dark hallway, you just draw that part up. Then lets say they walk a few feet, and spot an intersection in the hallway, once they spot it, you can instantly draw it up on the board within seconds, and draw out the dungeon as they traverse it.
As for miniatures, no need to buy any special miniatures or anything, just use some coins or erasers or something. (our group actually uses my friend's piles of warhammer miniatures as our characters, but really it doesn't matter what you use). Hell, you can even cut out a square piece of paper the size of a single grid, and mark it as your guy or whatever. (I actually made out of paper giant 'miniature' like game pieces, like dragons and stuff that you can throw on the board and move around with ease, and also like ships, with grids on them, that you can move around the board easily while your players are all standing on the ship).
Now DMing can be pretty difficult if you don't know all the rules. What I did to help myself out, was write out a bunch of easy to go to rules, like making a whole page of "combat rules" which has in all the rolls and stuff for all the different combat things, like fighting defensively, charging, overrunning, grappling and so on. Another way, is get those sticky tab things and put them on the more common pages in the books which get looked up for rules regularly so you can easily flip to those pages on the fly.
You can also spend a whole day, reading the entire players and DM manual, writing notes down for some of the more complicated rules and eventually you'll learn them. Admittedly the going may be slow when you're trying to figure out the rules until you start knowing them all by heart.
Another thing to help DMing, is to gradually add in new elements for each new encounter, and learn them as you go. So like start your first encounters with basic battles, then start adding in environmental variables, then add in monsters with like poisoning or whatever, then start adding in mounted combat and so on. Do that for every encounter, and by later in the game, you end up knowing all the rules on the fly, and can do very complicated encounters with ease.