That's actually a hard one at the moment: Developer editions of the Pandora have been shipped already since may (100 select developers received a DIY, semi-prototype version, in order to get software development running).

Normally, commercial versions of the Pandora should ship in July, but the makers have hit a snag: The manufacturer of the analog "thumb sticks" (game controllers) has unexpectedly bailed out. There are replacements available, but they are all compromises and the community is still arguing about it. At the moment, august is put forward as a reasonable shipping date.

Keep in mind that the original production run will "only" be 3,000 units, but new runs are dependent on its success and, given that the first 3,000 are likely already spoken for (there are no preorders possible yet, but the preorder mailing list is rather full, I'm told), I shouldn't worry if I didn't get one of the first batch.

Dimension wise, the Pandora is a little bit larger than a Nintendo DS Lite. It is quite pocketable.