That's what I was thinking. I'm currently leveling tailoring on my priest as well, and once I get to 350 tailoring, I'm switching to frostweave.
I'd recommend staying with netherweave as long as you can. It is much, much easier to farm netherweave and you're going to want all the frostweave you can get later on.
@OP: Frostweave farming.
One good spot for grinding frostweave is in the west-central part of Icecrown. The Converted Hero mobs drop 1-4 cloth 40% of the time. The mobs are yellow, so you can pick them off at will. There are solo mobs and groups of 5-6 mobs that you can pull if you are able. Kill the banner carriers, too, to weaken the Converted Heros. These mobs are part of a Tournament daily, but there always seems to be plenty up to kill.