Skype became the latest VoIP company to offer on-the-go service for Net-based calling.

Skype bundled its software with SanDisk's Cruzer Micro and Cruzer Titanium USB Flash drives, which take up about the same amount of space as a stick of gum.

The SanDisk Cruzer Source: Skype

The agreement with SanDisk enables Skype users to carry their calling contacts, settings and preferences on the USB devices, which are often called "stick phones."

The devices, which carry Skype's logo, include one free month of voicemail and allow users to check messages even while on-the-go.

SanDisk has captured 35 percent of the USB smart-drive market, according to Carlos Gonzalez, senior director of USB at SanDisk. 100 million flash devices will be produced worldwide, 30 percent in the U.S., Gonzalez said.

The Skype bundle is part of SanDisk's U3 platform, which allows applications, such as antivirus, file synchronization and password management, to run directly from the USB smart drive.

The drives are available in retail outlets and at Skype's online store, ranging in price from $39.99 to $199.99 with storage capacities from 512MB to 4GB, according to a statement.

Rival Vonage last month unveiled a similar USB VoIP smart drive product.

The Vonage V-Phone Source: Vonage

Vonage's V-Phone bundled the Internet phone service's software on a 256MB Flash drive. The V-Phone costs $39.99 plus $9 activation, according to the Holmdel, N.J., company.

A Skype spokesperson denied today's Flash drive bundle was a response to a similar Vonage product.

In related news, Vonage acquired three patents, giving what it says is control over pending patent-infringement lawsuits from Sprint and Verizon.

Purchased for an undisclosed amount from Digital Packet Licensing, the three patents involve compression of packetized digital signals, according to a Vonage statement.

However, Klausner Technologies put its hand in the patent-infringement claim, saying Vonage's voicemail platform infringes Klausner's technology.