You could try AGS games website they have loads of point and clicks ,most are free but you can also also check out their forum
for ' AGS Games in Production ' a lot end up as paid games.
Visionaire games forum post some free demos and info for new games coming out .
adventuregamers .com have loads of reviews for point and clicks and also a regular article on the latest and best free ones.
gameboomers .com is also a good place to find out about new adventure games and also forum to ask questions