Bellevue-based T-Mobile's introducing a new device taking advantage of its new 3G network: A nifty little USB stick modem for laptops with capacity for up to 8 gigabytes of storage.

It includes a slot for a micro SD memory card, plus a SIM card in a finger-sized black dongle.

The "webConnect USB Laptop Stick," made by Huawei Technologies, is handsome but not cheap. It costs $49.99 with a two-year contract, $99.99 with a one-year contract or $249.99 by itself. The micro SD card isn't included.

Service costs $59.99 for up to 5 gigabytees of data over 3G, plus unlimited data through WiFi hotspots (any hotspots, not just those operated by T-Mobile). Additional 3G time is billed at 20 cents per megabyte.

To warn customers before they start facing overage charges, T-Mobile added some nice software features, including a usage meter and a notification system that sends a message when you've used 80 percent of your 5 gigs.

Jeremy Korst, director of broadband products and services, said the device provides download speeds of 600 kbps with peaks over 1 megabit per second.

"For the majority of customer use cases around web browsing, social media, MySpace, checking email - all those typical things we see our customers doing more and more while on the go, the speeds we're providing now are more than sufficient to provide that customer experience,'' he said.

T-Mobile's hoping the software and overall polish of the product will help it compete against similar USB modems offered by Sprint, Verizon and Clearwire.

Software comes in the stick and unpacks and installs when you plug it into a laptop. It took me about 15 minutes, including a restart, to get going with a test unit T-Mobile provided - I used it to write this blog.

The "connection manager" software gives you three big buttons - WiFi, Broadband and VPN, so you can choose which way to connect.

I haven't tried this yet, but Korst said the system will alert you when WiFi becomes available so you can switch over and save your 3G time.

In an unscientific, quickie test with the modem showing four out of five bars of 3G reception, I played a YouTube clip at regular resolution with no buffering interruption. In high def, the clip buffered about five or six times.

Korst said there are no bundle offers or discounts for customers with other T-Mobile plans. Maybe that will change after Clearwire's new service is widely available.

As for T-Mobile's 3G network, Korst said it should reach an additional 100 cities - in addition to the 130 served at the end of 2008.

T-Mobile previously offered a USB modem that used its slower EDGE network but that device has been phased out.