[MENTION=38165]HillRider[/MENTION] made a good point about ERD. The ERD needs to be the same if you want to re-use spokes. If the new rim has a different ERD, you'll need spokes of a different length.


Wheelbuilding isn't that difficult. Find a guide to help you (plenty online) and follow the directions scrupulously.

You'll need a real truing stand to finish the wheel build, and you might want a spoke tensiometer.

I've built a couple wheel sets. I do the lacing and preliminary tension at home, and then I finish it in a truing stand at the shop or the bike co-op.

You could probably lace the spokes yourself and have the shop finish the build.
But, I'd contact the shop first to see if they're OK with that. They may prefer to do it all themselves, because they'd hate for you to bring in an improperly laced wheel that would take them LONGER to fix. Most shops build lots of wheels, and then can do it pretty quickly.