A USB memory stick that doubles as a portable VoIP (voice over IP) phone and a 16GB personal storage device the size of a credit card were just two of the devices shown off at CeBit that combine flash memory and USB in interesting ways.

The memory stick can be loaded with Skype's voice-calling software and comes with an attachable headset, allowing a user who is on holiday or working on the road to plug it into virtually any internet-connected PC and use it to make their VoIP phone calls.

Also equipped with an MP3 player and video player functions, it comes in three storage capacities: 512MB, 1GB and 2GB, according to developer A-Data of Taiwan. Users can load their phone books and other information on the device, and use it anywhere they can plug it in, said Jess Huang, from A-Data's marketing division.

It's just one example of the interesting uses companies are finding for USB memory sticks. A wave of devices are coming out that carry people's entire email system, television settings or internet bookmarks and passwords, so that a user can plug into any computer and use it almost as if it were their own.

Another example is the SmarThumb software from Malaysia's Intranet Sendirian Berhad. The program includes email, addresses, bookmarked websites and other personal data and runs from a USB memory stick or MMC (multimedia card) flash memory card. The email box works with Gmail and Yahoo and will soon work with Lotus Notes, according to Daniel Teh, product development manager at the company. The company is selling the software directly to USB makers, he said.

Users looking for massive storage capacities in a device that fits in their pocket could look at the 16GB disk developed by Power Quotient International of Taipei. The device is shaped like a thick credit card and fits easily into an average wallet. A USB plug pulls out of the back for use with any USB-ready computer.

"Since it's designed to fit into a wallet we had to make it very strong," said PQI's Joseph Lu. The outside is metal and there is a plastic frame inside to protect the flash chips, he said.

"It's a bit more expensive to use metal, but we figured plastic casing just wouldn't be strong enough," he said.

The device will be in mass production by May and available worldwide by the middle of the year, according to Lu. Pricing has not yet been set.

It was by far the largest-capacity mini personal storage device on display at CeBit. Small keychain USB sticks were available in up to 4GB sizes, but no larger.

Flash storage is also increasing suitable for camera buffs. A few companies showed off 8GB CompactFlash cards, including Goldenmars Technology and Silicon Power.

Another type of device doing the rounds at CeBit is a USB drive with a single slot that reads multiple memory-card types, so users with digital cameras or other devices that use MMC, SD and other cards can carry one USB card reader around.

Candy Technology had several keychain USB drives that are already shipping, including one that reads Trans Flash cards, SD cards, mini SD cards, MMCs and RS-MMCs (reduced-size MMC cards).