While I can't speak for wargames, there are pdf versions of other tabletop books available, ---- I indeed have some of the books for mutants and masterminds. when I originally got these though the text converted fine, the tables had some options, however with some of the updates to adoby reader, ----- pluss making certain I use the accessible version of the program and not the usual one, these come out okay even with tables.
Really, Adoby should make it clearer that there are! two versions of the program, and the bog standard version doesn't either convert to text or run with screen readers too well.
Anyway, you can find the accessible adoby reader at http://www.adobe.com/accessibility/products/reader/ and you can get rpg rule books from http://rpg.drivethrustuff.com/
I believe they may sell war game related stuff as well, but I'm not absolutely certain about that.
Either way, now that there ar programs to manage things like character and enemy stats and more gms' use laptops (our mutants gm certainly does, in fact he's a beta tester for hero lab, the mutants gm helper program), I think books in electronic if not accessible format will become more common.
I do wish though they would publish the newly released gamebooks in the fighting fantasy and lone wolf series in a none paper form, ---- but sadly not!
Some funky touch screen applications for I phone, but nothing that will work with a screen reader sadly.
anyway, that's another debate entirely, I stil hope you find that stuff useful.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)