The manual confirms:

• Memory cards, PSN accounts and PS Vita hardware are inexorably entwined after all: "After you sign up for PlayStation®Network from your PS Vita system, memory cards that you insert are linked to your PlayStation®Network account. You can only use the memory cards in PS Vita systems to which the same PlayStation®Network account is linked."
• You'll hold down the power button for five seconds to turn it on, and two seconds to turn it off.
• Like the PSP, there's also a standby mode if you tap the power button once or wait long enough. Wi-Fi and cellular keep running while the Vita is in standby, so it can deliver push notifications to you.
• You can take screenshots by pressing the PS button and the Start button at the same time, if you've got a memory card.
• You can have up to ten homescreens, and up to 100 program icons.
• There's multitasking: you can have up to six LiveArea screens at a time, and you can swipe up and down between them or view them all in a single menu. Each program and game has a LiveArea screen, which lets you engage in real-time chat and other social networking features, even if the game card itself isn't currently inserted in the system.
• You can copy save data from a PSP to a PS Vita, as long as you transfer it to a PS3 or PC first.
• You can only download standard-definition (SD) videos from the PlayStation Store, perhaps because 1080p HD playback isn't yet supported. Oh, and you can't copy HD video from the PS3 to the Vita, either.
• You'll be able to monitor your 3G data usage.
• Battery life is "approximately 3-5 hours" while playing games without network use, "approximately 5 hours" of video playback and "approximately 9 hours" of music with the device in standby mode.
• It'll take about 2 hours, 40 minutes to charge the Vita with the AC adapter.
• You can optionally charge the Vita from a computer's USB port, though it sounds like it's a trickle charge. The manual says you should "turn off your system" while doing so.
• The system supports 18 languages and the software keyboard's language can be changed. It also has predictive entry with a customizable learning dictionary.
• You can optionally use the microphone in your Bluetooth headset instead of the PS Vita's own, presumably in games and not just for chatting with others.
• Wi-Fi security includes WPA-PSK and WPA2-PSK, and there's an ad-hoc Wi-Fi mode.
• Sony's "near" location-based social network collects your location data only every 30 minutes automatically, and only displays it for PSN members over 18 years of age, and you can change it to manually update or turn it off entirely.
• The Photos application supports JPEG, TIFF, BMP, GIF and PNG format images.
• The Videos application only supports H.264/MPEG-4 AVC up to 720p resolution with AAC audio, but does do High Profile content. You can change audio and subtitle languages and options.
• The Music application supports MP3, MP4 and WAV.
• You can use the PS Vita as a remote control and screen for your PS3, even over the internet. You can't play Blu-rays or DVDs, though, and there are a variety of other undisclosed limitations.
• You can backup and restore your Vita's files to a PS3 or PC.