ZDNet has an interesting story
about hardware solutions for the Presidential Crackberry obsession. It turns out Obama may not have to give up his PDA after all, there are some secure options out there based on Windows. The article doesn't specify what flavor of Windows, but I'm going to guess CE as opposed to Windows Mobile.
Coming from a Defense Department project called SME-PED (Secure Mobile Environment Portable Electronic Device), the $3,350 Sectera Edge at least comes with a two-year warranty. It looks like there are still some obstacles (only covers data up to 'secret' classification), but it's a better choice than off-the-shelf hardware.