The useful nerd

Quick Reboot lets you reboot (or boot) your phone in several different modes including recovery or bootloader. Free, this app works across all Android devices. With Quick Reboot, you can also make home screen shortcuts for booting in one mode or another, with just one click.

Tether your computer to the Internet, using your Android phone. Skip the Bluetooth, and get the PdaNet app. It gives you the same connection you get mobile browsing, and comes with an SMS Agent, so incoming texts and Google Talk messages push through to your computer.

Mobile browsing has improved greatly on Android devices, but the Dolphin Browser has stayed a step ahead. Free, this Android app is optimized for mobile browsing, with Gesture, multi-touch, tabbed browsing and RSS feed integration. You can sync your Google bookmarks, choose a theme for your browser, and customize settings for your privacy.

Swype comes on several Android devices now, but the rest of you can still download it. The text input designed for mobile screens makes you more efficient at using your keyboard, following your finger’s motions. Free, Swype lets you write faster, with less toggling, so you can stay on the move.

Gmail is useful on the Android, but K-9 Mail has a few extra perks. Free, this app aggregates and organizes all your email messages into a searchable, multi-folder tool. Flag and star items, attach signatures, customize alerts and more. An upgrade lets you copy and paste text, and report spam.

Smarts and entertainment

Techies tend to like original Nintendo games, so try Nostalgia.NES (NES emulator). For free, this Android app lets you play a number of Nintendo games, like Mario Bros. Customize your screen keypad and save key profiles, save games, and play other gamers online.

Did you see Jupiter, shining southeast of the full, harvest, equinox moon last week? You would have, if you used Sky Map. The free Android app offers detailed information of the heavens, outlining constellations and showing you the nightly path of the stars. Toggle between grid and regular views, learn about each constellation, and planets too.