The PS Vita will be able to do a lot of different things, from play games (its main purpose), to displaying photos and playing videos and music. In order to do this, it needs a variety of compatible media and file formats. Removeable media compatible with the PS Vita is listed first, followed by the different file formats the device is able to play.
We all know that Sony is a fan of proprietary formats for removable storage media on their devices, and the PS Vita is no exception. In fact, it gets not one, but two different PS-Vita-only card types.
PS Vita Memory Card: Where the PSP used Sony's Memory Stick Duo and Pro Duo formats for storage, the PS Vita will use a brand new PS Vita Memory Card. Presumably, the introduction of an all-new format is one trick in a range of things aimed at reducing piracy. Memory sticks like those used in the PSP will not work with the PS Vita, nor will other common formats like memory stick micro (as used in the PSPgo) or SD cards. In addition (and no doubt another anti-piracy measure), memory cards will be linked to a user's PlayStation Network account and can only be used in PS Vita systems that are also linked to that account. Presumably there will still be some way to use a memory card if the user never goes online and doesn't have a PSN account.
PS Vita Game Card: Rather than the PSP's UMD game media (which will not be playable on a PS Vita, though downloaded PSP games will), PS Vita games will come on PS Vita Game Cards. These are cartridges rather than optical discs (like UMDs). Some games will be able to store their save data and even downloaded add-on content right on their PS Vita game cards, while other games will require a PS Vita memory card for save data. For games that use the game card, save data cannot be copied or backed up externally.
Sim Card: PS Vita units with 3G connectivity will require a sim card from a service provider in order to actually use 3G. This is the same kind of sim card as used in cellphones.
The PS Vita, while primarily a gaming handheld, is also a full-featured multimedia device, capable of displaying images, and playing music and video files. It supports the most common file types, but it can't play everything (no Apple-native sound files, for example). It's likely that the device's capabilities will be expanded as time goes on and new file types become popular, but here are the file types are playable right out of the box.
It's nice to see tiff support on the PS Vita--not all portable devices have it, which often means converting higher-quality images into continually-degrading jpeg files to view them. Of course, tiffs are usually much larger files than more compressed formats, so better quality comes at the expense of storing fewer images. Otherwise, all the major formats are here, ensuring that you should be able to look at just about any still image.
If you download a lot of music from the Apple store to iTunes on your Mac in AAC format, you won't be able to listen to all your music on your PS Vita (but if you're using a Mac, you won't be able to use the PS Vita's Content Manger Assistant software, either). This is a bit of an odd omission, since AACs are playable on the PSP. There's also no support for AIFF files, but since that's primarily a format for burning to CD and not for portable listening, that's not as big a deal. Other than those two, the most popular sound formats are supported.
Yep, one whole video format is supported. Sure, it's the most common one, but still. Maybe Sony will add support for other file types in future firmware updates.