Increasingly, PDAs are becoming a critical tool for physicians. For example, according to a Manhattan Research report, the penetration rate is over 50% -- which compares to 30% in 2001. There are certainly major benefits, such as patient safety, compliance, and improved productivity.

One of the top operators in the space is Epocrates. And the company has recently filed to go public.

Basically, Epocrates has a huge database of clinical information and decision support systems that are delivered wirelessly. Just some of the information includes: dosing, pricing, insurance coverage, and disease diagnostics. The subscriber base is in excess of 500,000.

Epocrates is also an effective marketing channel for healthcare companies -- in terms of providing market research and alerts.

And yes, revenues are growing nicely. In 2007, Epocrates posted revenues of $65.6 million, up 33% over the prior year. Cash flow from operates was a hefty $23.4 million.

The lead underwriter on the IPO is Citigroup, Inc. (NYSE: C) and the proposed ticker is "EPOC." You can also find the prospectus at the SEC website.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates MergerBook.com.