(Note: the following is for heavy fighting leather gauntlets, not rapier fighting gauntlets.)
Damon,
First leather project? Good man! I'd suggest, though, that you tackle a slightly easier project first, just to get used to working the leather. For me, I made a set of vambraces. Nothing special or fancy, just 2 pieces of leather in a trapezoid shape with eyelets for lacing onto my arms. They give you a chance to make the simple mistakes w/o getting frustrated to the point of violence

As for the gauntlets, I've made them using the following pattern:
http://www.meridies.org/as/dmir/Arms&Armor/02/0220.htmlA few pointers from my experience. First, is this for SCA fighting? If so, read on. The second is, do I block with my hands a lot? If the answer is YES allow me to suggest getting a decent set of steel gauntlets instead of the leather. Leather protects great against the occasional hit and glancing blow, but they are far from the durable, constant protection of steel. Myself, I avidly aviod blocking with my hands (comes from swordfighting with hockey sticks in my youth without gloves

) so leather works fine. If you're in the same boat as me (don't block with hands) I still recommend you harden the leather (Do this after the holes are punched but before assembly). I prefer the hot water method myself, others prefer the beeswax method. Here are some links to both:
http://www.pbm.com/~lindahl/cariadoc/perfect_armor.htmlhttp://www.daviddfriedman.com/Medieval/Articles/Perfect_Armor_Improved.htmNow, if you're going to use the gauntlets as decoration more than functional (or play with a light hitting group that uses padded weapons)there is no need to make the main plates out of sole leather (12 ounce or thicker) I would suggest making them out of veg-tanned leather though. Light (2-6 oz) oil or alum tanned leather is very flimsy and doesn't hold the shape well, but works great for the rectangle pieces that are really "straps" that hold the thicker protective pieces together. Myself, I used 14 oz leather for the plates, 6oz oil tanned for the attaching straps, and 10-12 oz for the cuff. They've worked fine for my purposes.
OK, Tools. The article suggests an exacto knife: I recommend a trip to wal-mart, home depo, or lowes and drop $10-30 on 2 very important tools: tin snips (for cutting the leather) and a roatary punch (for the holes). Well worth the investment.
For rivets, RJLeahy (link in the armour supplies section here at the archive) is probably the best mail-order price around. Since it's the first project, get the copper belt rivets w/ burrs. You may consider getting a rivet setter from Tandy leather (or other leather store) but a piece of pipe whose interior diameter fits the rivet shaft will work just as well. This is for setting the burr on the rivet.
(if they are decorative gauntlets, consider pop rivets. they are cheaper, easier to set (and look pretty, too)
During construction, the thumb plate needs to go on last, after the finger plates, knuckle plates, hand plate, and cuff plate are done and the gauntlet has been strapped for the hand. Do it sooner and prepare to be frustrated. Also, his design for a thumb guard is a bit odd, I ended up remaking mine to suit my own tastes. YMMV.
Finally, consider sewing or riveting a work glove to the gauntlet in addition to the straps. This helps enormously.
Good luck.
Paul