Start-up touts answers for VoWi-FiStart-up Divitas Networks is expected to debut this week with technology for tying together corporate wireless LANs, cellular networks and Wi-Fi hot spots as one mobile voice and data network. Click here for more.More turning to telecom expense toolsTelecom expense-management tools and services aren't new, but more businesses than ever are finding them necessary. Reasons include the fact that service providers continue to bill customers in error, of course, but also the ongoing concerns over industry consolidation - as well as outright scams. Click here for more.Microsoft warns of HP patch problemUsers of HP printers, scanners and cameras may be experiencing some problems after installing Microsoft's latest round of security patches, released late last week. The problems, which concern a Windows operating system patch, can cause some applications to crash, Microsoft warned Saturday. Click here for more.Protecting corporate dataAn internal user is downloading large amounts of credit card data. Do you know why? Tizor Systems' Prat Moghe gives you the answer on this week's Network World Hot Seat. Watch it now.Debate unsettled over costs, benefits of certificationIt's not hard to write the initials after the name of a networking professional: CCIE for Cisco Certified Internetwork Expert, or CNE for Certified Novell Engineer, among dozens of others. The initials mean that someone is a certified professional for a specific task or product. But before going through the process of earning such a certification, a networking professional should determine whether those initials are worth the effort necessary to acquire them. Click here for more.Today on Layer 8, where we say "Katie Holmes, run for your life!":Microsoft wants to get you a date with a celebrity; is D-Link messing up the 'Net's sense of time?; security concerns hamper e-filing; and the start of our latest Weekly Caption Contest; all this today and more at your home for not-just-networking newsFor news updated throughout the day, go to Network World's NetFlash news page.