The Modu modular cell phone is a really interesting idea. Its timing may be perfect, or not. It may spawn its own ecosystem, or not. It’s design, interface, and support products may hit the bulls-eye, or be total cheese.

But you’ve got to give Israeli startup Modu credit for trying something different. Modu is introducing a tiny modular phone that can be slipped into different “jackets” to give the base phone additional features and functions depending on the user’s needs.

Basic “jackets” may include an MP3 sleeve, turning the phone into a digital music player. Or a GPS device. Or a digital camera for wireless image transfers. Or an alarm clock interface. Or with a larger screen, a video playback device. The possibilities are plentiful.

The phone module weights just 1.3 ounces and is smaller than a credit card. It will launch Oct. 1 with mobile carriers in Russia, Italy, and Israel, but not in the U.S. or elsewhere in Europe at this time. It will be on display next week at the Mobile World Congress in Barcelona.

If Verizon Wireless is truly the winner of the FCC’s 700 MHz spectrum auction, as many industry experts now believe, the No. 2 U.S. wireless carrier must live up to its promises.

Promise: On Dec. 4, Verizon said it would support the Google-led Open Handset Alliance. By doing so, Verizon, a notoriously protective carrier known for its iron-fisted rule over the devices and software applications running on its network, said it would support the open network initiative.

Promise: At the same time, Verizon said it would support the Google-powered open-source mobile operating system Android. By doing so, Verizon said it was willing to allow phones from any manufacturer — even those using the Android platform — to run on its network as long as they meet Verizon quality specifications.

Promise (and one it can’t worm out of): If Verizon does win the C block in the 700 MHz spectrum auction, it must — as a stipulation set forth in pre-auction rules — open the new network to any phone running any software.

Forbes speculates that “analysts believe Verizon — thought to be the only bidder besides Google that is both rich and motivated enough — is poised to win the coveted C block of spectrum that Google has been eyeing.”