.... in the "game"!
First of all Let me welcome you to the RDINN fellow inmate and kudos to you for rising up to the rank of "occasional visitor" in such a short time. You weren't a newbie for long were you?
Also, way to go on choosing to go the "hard way" first with DMing. Ive been DMing since 2002. My first game was a homebrew, but you have one advantage I didn't have: newbie players. All my players were seasoned and well versed in the rules so I felt quite embarrassed when I would make a rules mistake and the players weren't shy about letting me know it.
I have to concur with my fellow innmates on these points:
The most important thing is that you and the players have fun. It's the main thing that will keep your players coming back session after session.
And to add my two cents worth on having fun, Everyone deserves to have fun during the game, even "Rules lawyers". They are the ones that have read all the rule books 20 or more times. Its the D&D books they read to their kids and then read themselves before going to sleep. lol jk (I think Im kidding anyway). Its fun for them to know all the ins and outs of the game's mechanics. Therefore rather than glaring across the table at them everytime they say,"Ahem....point of order...", put them in the capacity of "Lore Master". Not only will that player be able to play a character but is also charged with assisting the DM/GM with making adjudication decisions that more closely gell with the rules, and to be ready at a moments notice to QUICKLY find said rules in the books to back it up.
I also agree with Celeste on every point she made in her blog on Epic GMing. Even here on the Inn I use maps. I upload them to Photobucket and paste a link in pms to my players.
The best DMs I know are both preimptively creative and can think on their feet and/or fly by the seat of their pants. A living breathing world with towns or cities with NPCs and working government structures is great, but an invaluable skill is to create towns and NPCs on the fly straight outta your head, and if you get really good, whole dungeons too. That is a skill you will have to practice to perfect, though.
If there are any books you don't have, I can email you the pdfs of most dnd 3.0/3.5 ed books. Just let me know.