Five must-have iPhone apps coming soon

Voice search, an offline RSS reader, a Twitter client, and even streaming satellite radio—just five of the upcoming iPhone/iPod Touch apps I'm dying to try.

Gina has already blogged about the upcoming iPhone apps that were announced during Apple's WWDC keynote earlier this week; since then, more developers have been revealing their plans. Here are my five favorites so far:

NetNewsWire
One of my personal pet peeves about the iPhone is its lack of an offline RSS reader—a feature that would make my daily commute in the NYC subway system go a lot faster. Well, good news from Ars Technica: The developer of NetNewsWire, one of the best desktop RSS readers for the Mac, is working on a stripped-down version for the iPhone. Read all about it here, and look for NetNewsWire to sell for the bargain price of nothin' once the App Store launches.

Nuance OVS
Unlike even some of the most basic cell phones, the iPhone won't respond to voice commands—or not yet, anyway. Voice recognition developer Nuance showed off a prototype iPhone app earlier this week (code-named OVS, for "Open Voice Search") that'll let you bark commands such as "Score of the New York Mets game" or "Find the Apple Store in San Francisco." Future versions of the app will even let you dictate SMS or e-mail messages, Nuance says. No pricing or release dates quite yet.

SlingPlayer Mobile
You can't access AT&T's mobile video service over the iPhone 3G—but if you're already slinging your favorite shows from your DVR to your iPhone, who cares. SlingMedia gave CNET a sneak peak at its version of SlingPlayer for the iPhone, which is designed to take advantage of AT&T's speedy HSDPA network. Pretty cool, but Sling reps say their iPhone app might not be ready until next year.

Twitterrific
The popular Twitter client is going the iPhone way, reports The Unofficial Apple Weblog; details are sketchy, and there's no pricing info yet, but Twitterrific for the iPhone/iPod Touch should be ready for the App Store launch.

XM Radio
The satellite radio provider—which already makes mobile apps for various cell phones, including BlackBerrys—revealed earlier this week that it's building a version of its XM Mobile Radio app for the iPhone. Now, it's not clear how much XM would charge for the service (although Ars Technica notes that BlackBerry users pay $9 a month for their XM tunes), nor is it clear whether you'd be able to listen to XM Radio over AT&T's HSDPA network—although if that happens, it could help make up for the fact that you can't (for now, at least) download iTunes songs over HSDPA.