I've tried grosgrain watch bands -- a trad classic -- in the past week for the first time. I purchased mine through the mail from Central Watch in NYC after seeing them recommended on the Ask Andy forums. (They're sold in sets of five for about $35 shipped.)
As I anticipated since I have small wrists, the only problem was that they were too long; this is one of the reasons I dislike leather bands -- because you can have the links on a metal band removed to make the watch fit snugly, as it should (there's little worse style-wise than seeing a man who's wearing a metal watch gesture upward with his hands and seeing his watch slide half-way down his forearm).
I had seen discussions on Ask Andy about cutting these bands to size.
Some recommended just adjusting the strap on the buckle side, which loops the extra ribbon across the back of one side of the band; I tried that and disliked it, both because it makes the band on one side of the watch have holes all the way up to the watch, and because it felt weird to have half of the band be twice as thick as the other half.
I couldn't have about four inches of extra band flopping around, so the only solution was to try cutting them.
I first cut about two inches off of the end of one of the bands, in order to use the curved end piece as a template. Then I put the band through the watch and put it on, to figure out how long it needed to be. After marking that place with masking tape, I taped the curved piece to the band at the taped point, then trimmed the excess band off around the curved template with scissors.
I had read that grosgrain ribbon can be "sealed" with heat so that it doesn't fray. Using the flame on my stove top, I grasped the band with tongs and held the cut end of the band about four inches above the flame, moving it all around in the heat, for maybe 10 seconds. It seems to have worked.
As I learned from testing this method first with the cut-off, scrap piece, if you hold the band in the heat for too long, it will burn the edges, rather than just sealing them, turning them black and ruining the band. So less is definitely more; if you still see fraying, you can always hold it over the heat again -- but, if you quit too late, you can't un-burn it.
Also, be sure not to let the band get too close to the flame, or you'll catch the band on fire and really burn it.
For more on grosgrain bands, see these entries from Heavy Tweed Jacket, Ivy Style, and Thrift Store Preppy (which has a great, close-up view of what one of these bands look like when worn; I put mine on the exact same Timex model, which I purchased at Wal-Mart for about $25).