—Rhapsody (free iPhone, Android or BlackBerry download; $9.99/month Rhapsody account required via Rhapsody.com)
What it is: A music-streaming app that lets you listen to as many songs as you want for as long as you want from a catalog of 10 million tunes without ringing up a charge for each one.
Why it's great: In the airport lobby or on the beach, you'll be thrilled to program your own soundtrack wherever you can get a 3G, 4G or Wi-Fi connection. Unlike iTunes, there's nothing to buy and nothing to download, so you can listen to one song while you continue to assemble your playlist. And unlike Pandora, you're in charge of what you hear next (unless you don't want to play DJ, in which case you can click on a playlist or listen to preprogrammed radio stations). Won't be near a hot spot? Download tunes to your phone to play back later.
Why you might hesitate: If you quit Rhapsody later, you won't have anything to show for your subscription fees. Rhapsody does give the option to buy a track ($1.29 for hits).
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Whom it's for: Android users will cheat themselves if they don't at least give this app a 14-day trial. And iPhone users who have amassed a huge iTunes library can augment their on-the-go pleasure.
—Living Language French ($9.99, iPhone)
What it is: A new basic course of 10 lessons for beginning French speakers.
Why it's great: It's a whole course from a trusted name in publishing. Repeat after the audio to perfect your pronunciation, then match phrases with flash cards to get the phrases into your head. Read sections that explain why and when to use certain inflections, and play word-matching games to ensure you have it down. You control the pace. With practice, you'll have a few useful phrases on your tongue before you know it. Not convinced? Try the free Lite version — it's Lesson 1 of the 10 Living Language French lessons.
Why you might hesitate: Lacking a way to correct your mispronunciations, you might develop bad habits
Whom it's for: Travelers to Quebec or France who need to learn fast.
—Hot Apps: Best Android Apps (free, Android)
What is it: An easy way to discover apps in the growing Android market.
Why it's great: Sort apps by most popular today, most popular of all time and most popular of 2010. If you tap the Discover tab, your screen will fill with small icons of apps. Touch one that looks interesting, or shake your phone to get a new screenful of icons. A fun way to find new apps you might find useful, fun or both.
Why you might hesitate: Some users have complained that links to apps don't work or that Hot Apps doesn't work well on their phones. We found no problems on a Nexus One, and c'mon, it's free!
Whom it's for: Anyone looking for something new to spice up the day.