According to Half-Life Source Half-Life 2 is getting pretty close to completion, with the game going gold in August and then hitting stores in September. Here's what they had to say

According to recent conversations we've had with Valve's Doug Lombardi, Half-Life 2 will be passed on to publisher Vivendi for final mastering and duplication within days for it's early August target. The official appearance will make store shelves sometime in mid to late September.