That lens will work with every Pentax DSLR (a great thing about Pentax is backward compatibility). Two points though:
1. Its a question of comparable field of view. If you go for a APS-C camera (K-x, k-r, k-7, k-5, k-30, k-50, k-70, k-p, k-3, k-3ii or earlier digital bodies) then there is a 1.5 "crop factor" in play. so 28mm on crop as the equivalent field of view to a FF 42mm lens. If you want to get the fullframe (original field of view) then you would need a K-1 or K-1ii, which are fantastic cameras but obviously a significantly more expensive option.
2. As a starterThe FA 28-200 is a decent enough performer on digital (see reviews:
SMC Pentax-FA 28-200mm F3.8-5.6 AL [IF] Reviews - FA Zoom Lenses - Pentax Lens Reviews & Lens Database) to start with but its possible you may soon crave something with a higher image quality (its known as Lens Buying addiction or LBA) as modern digital has a habit of showing all the imperfections in a lens (and even a few that would not ever show up with film!). Also if you settle on APS-C then for the same field of view range you would need a lens with a focal range of 18-135 (like the DA 18-135) which is also a better performer than the FA 28-200.