Sprint, its cellular division Sprint PCS and Cingular Wireless–say they have created wireless messaging services that are secure enough for use by corporations and their mobile work forces.

The new services, two of which were launched Monday, are expected to put pressure on Research in Motion, the maker of the popular Blackberry wireless paging devices that now dominate the wireless corporate e-mail market with approximately 289,000 subscribers. Most are corporate clients, among whom the devices have the nickname “Crackberry” because of their addictive nature.