Understanding AdSense...

while trying to change my layout (i failed miserably, maybe due to connection error) i was suggested adsense. by puttibg adsense, i'm getting paid for every advert clicked on my blog. tempted, i was so tempted. that's why i saw so many adverts at my bfriends blog. they acttually have this, while i knew nothing.
however, by having advert on my blog, it kinda actually slow down the page loading. i just hate that.
but i get money, rite (not immediately)?
i'm still weighing in all the options....