Greatest free chess program going around is maybe Scid vs. PC
It's a fork of an established chess database program,Shane's Chess Information Database
, with an emphasis on improving the GUI and shifting the focus from databases to a general purpose chess program.
The latest release includes a Computer Engine Tournament, a decent gamelist widget as well as the usual numerous cut and polish improvements of every release.
There's a lot of scope for a chess article too - though, most every program still s**ks in some way. Scid vs. PC
's power and flexibility means it is still a little indecipherable to casual users, but perseverence is rewarded by a hugely powerful Chess App.