I don't know much about Josh Powell, can anyone talk me through his game?
Not a lot to him. Solid size at 6-9 240lbs. Good quickness and mobility. Was an average rebounder earlier in his career but firmly below average in last two seasons (one with LA, one with Atlanta). A serviceable defender. Limited offensive player. Has a decent a midrange jumper (14-18 feet). More of a midrange jump-shooter than a finisher around the basket (which he's weak at).
His physical attributes are his best asset. Allows him to matchup effectively (as a defender/rebounder) against most PFs and avoid putting his team at too much of a disadvantage. Unlike say JJJ who is rail-thin and is liable to get pushed around by any PF with good size/strength.
Had a couple of good seasons for the Lakers as their fourth big in a three player big man rotation ... which is the right type of role for him. A third string PF who is useful filler but not talented enough to be a rotation guy.