There's a budding travel trend on Twitter.com. The micro-blogging tool on which users send short messages, or ''tweets,'' has become a hot networking tool for the Web-savvy travel community. Airlines and hotels reach out to their customers and offer personal service and tips, while travel bloggers befriend and keep tabs on colleagues. But what about the average consumer? Bargain-hunters can cash in on travel giveaways and sales. We recently found @fairmonthotels running Twitter-only contests and giving away gift certificates, stays at Fairmont hotels, DVDs, CDs, backpacks and more to its Twitter followers, and @NapaMarriott running another contest for its Twitter followers. Besides hotel-stay giveaways, it answers questions about the Napa Valley area and gives advice on restaurants and wineries.