If it is a very large quilt, I will split the sleeve in the middle so I can give the quilt some extra support in the center.

Margo's suggestion about consulting each contest's rules for sleeves is a good one. For submissions to Paducah (and maybe other AQS shows) the rules are very specific, as they have acquired a new hanging system. The website for the contest has a downloadable set of instructions that are very clear with good illustrations.

Thank you so much! That 9-inch measurement is exactly the information I needed. Great site... it's now been bookmarked.

Now it's up to the sewing room to get this baby DONE!!

WOW! That link gives GREAT directions and that's how I do mine when I attach the whole thing by hand.
When I make a permanent sleeve, I just skip the seam part, and put both raw edges at the top before I add the binding. (That is described in page two of Terry's link.)
In order to get the extra fullness (and some quilt shows now require this!) so that the hanging pole or system does not distort the front of the quilt, I just make a pleat at the top large enough that the sleeve doesn't show from the front, then stitch the bottom in place.
If it's for a show, be sure to read the entry requirements to see how wide they want the sleeve to be. Most require a 4" sleeve, so I usually cut my fabric 9", just to be sure!

Hi--check out this web link for directions:
http://quilting.about.com/od/decoratingwithquilts/ss/quilt_sleeve.htm

When you hand stitch the edge, leave 1/4" ease so that there will be a bit of pooch to the sleeve. This pooch helps the quilt hang straighter. Best wishes on finishing your project soon. Terry in Oregon

I'm finishing up a quilt - fairly large - that will be hung on a wall. It needs a hanging sleeve but I don't remember - and can't find - the dimensions or width (depth?) it should be. I will be sewing it into the quilt while attaching the binding, and remember to give it a little "ease" when hand-sewing the bottom down. But just how large of an opening is needed? Sorry if that's not really clear... ...but maybe some quilter will know what I mean.
Thanks in advance.