RIM BlackBerry Curve 8320

First came the trim, consumer-friendly BlackBerry Curve 8300. Then came the Wi-Fi-enabled BlackBerry 8820. Now there’s the BlackBerry Curve 8320, an impressive PDA phone that combines the best of the previous two models and has an added bonus: While the 8820 supports Wi-Fi for data only, the 8320 lets you make voice calls over wireless 802.11b/g networks too.

Physically, the 8320 is the same as the original BlackBerry Curve, though it comes in two different colors, titanium gray or gold. (Unlike the original Curve, which is available from AT&T, the 8320 is available from T-Mobile for $300 with a two-year contract.) It features the same thin and light design, a small but very usable QWERTY keyboard, a 2-megapixel camera, and a gorgeous 320-by-240 display.

The biggest news is under the hood: In addition to support for GSM voice and EDGE data networks, the 8320 adds Wi-Fi with UMA–a technology that allows you to make voice calls over Wi-Fi. The phone works with T-Mobile’s $20-per-month (on top of your voice and data plan) HotSpot@Home service, which permits unlimited calls over Wi-Fi networks. While the service is a bit pricey, it could potentially lower your costs by saving your cellular voice minutes.

I tested the phone and the service using one of T-Mobile’s HotSpot@Home wireless routers, manufactured by Linksys. Using the 8320’s on-screen wizard to connect to a wireless network is a breeze; within just a few minutes, I was surfing the Web and downloading files with ease. The 8320 will connect to any 802.11b/g wireless network, so you can use your existing router–or even a public hotspot–to make calls and surf the Web.

T-Mobile says its router (priced at $50, but free after a rebate) is designed to conserve your phone’s battery life and to prioritize voice traffic, which should–in theory–result in better call quality. However, I noticed no significant improvement when using the T-Mobile router instead of my own Linksys wireless router. Call quality over both wireless networks was the same: decent. Voices were garbled sometimes, and I noticed an echo, just as I often did when using the phone over a regular cellular connection. Being able to make calls over Wi-Fi is a great option in areas (like my house) where cellular service is spotty, though. (We could not lab-test the phone’s talk-time battery life in time for this article’s initial posting, but we will update this review when we have the results–and the PCW Rating for this phone.)

For both voice calls and data usage, the 8320 will default to your Wi-Fi network when it is available. Should you leave the network’s range, the phone is supposed to switch your call seamlessly to the GSM network (and vice versa)–but in my tests, the experience wasn’t as smooth. When I went out of range of my Wi-Fi network, my calls occasionally dropped, even though cellular service was available.

Those glitches aside, the 8320 is an excellent phone. Like all BlackBerry units, it is a stellar e-mail device, with support for ten accounts. The included camera (which sports a flash and a 3X digital zoom) took adequate but–like many camera phones–occasionally blurry snapshots. Among other multimedia features is an audio and video player that supports most formats (including MP3, AAC, WMA, WMV, and MP4). The player’s interface is basic, but audio quality is good and video looks great. The device also has a 3.5mm headphone jack and a microSD card slot (which is inconveniently located under the phone’s battery, unfortunately).

While voice quality over Wi-Fi was only passable, the capability itself is still impressive. And combined with the 8320’s sleek design and awesome e-mail handling, it makes for a winning package.

–Liane Cassavoy