(FORTUNE Magazine) – Redwood Shores, Calif. Founded 1996

Wi-Fi has become as essential as roller-bags for business travelers, but companies building out the service haven't exactly been rolling in the dough. Broadband access provider iPass, however, has found a profitable niche in patching together the nation's crazy quilt of Wi-Fi locations--called hot spots--to enable employees of clients like General Motors and eBay to get secure access to the Net and corporate intranets.

Some 520,000 users in 30 countries from Switzerland to Singapore use iPass's software to access their corporate networks at hotels, airports, and cafes. CEO Ken Denman, 44, a telecom industry veteran, was able to triple revenues to $136 million last year from 2000. The company last summer raised $112 million in an IPO, though the stock now sits at $12.44, about $1.50 below its offering price.

Next up for iPass is to widen its Wi-Fi. Recently it inked a roaming deal with T-Mobile--the nation's largest Wi-Fi network--that doubles iPass's footprint to about 9,000 hot spots, including those at Starbucks and Kinko's. Now iPassers can keep in touch with the office--even while making copies of their resumes. --M.B.