ForeFlight Mobile 4.4 has added a way to store and view PDF documents on the iPad. ForeFlight provides versions of popular FAA handbooks, parts of the Airport/Facility Directory previously not available in this app, and chart legends for download and manages those files just like a chart subscription. This ForeFlight video explains the documents feature in great detail.
The document reader provides indexed documents and allows you to save bookmarks. Complex pages, like illustrations the one below from the FAA's Instrument Flying Handbook, can take a while to render (though they seem to render much faster on the new iPad) which may leave you with the impression that the page you selected is blank. Be patient and you'll see complex pages appear.
You can download and store enhanced Class B representations. Unlike SkyCharts Pro, ForeFlight still doesn't provide important Terminal Area Chart marginalia (like the VFR routings through LA Class B) shown below. Hopefully that will be coming soon.
To store your own PDF document in ForeFlight, simply need to email it as an attachment, open the email using the iPad Mail app, tap on the attachment icon, tap the icon in the right upper corner, tap on Open In ..., and select ForeFlight from the list of available apps.
For operators who want to distribute electronic copies of important company documents, like the latest version of their OpSpec, the ForeFlight documents feature should save a lot of paper, weight and heartache. ForeFlight continues to do a good job of balancing their app's feature set so that it is useful for individual pilots as well as commercial operators. ForeFlight also doesn't seem to be afraid to innovate and at this rate, the competition has a lot of catching-up to do.