GTA Online: this site will help you find a crew to play Heists with
If you're looking for an easy way to get a crew together and attempt a Heist in GTA Online, this website will make it very easy.
Similar to the various 'looking for group' sites for Destiny, an enterprising individual has created a 'looking for Heists' website that aims to make getting a group together pretty simple.
If you're a crew leader, you can list your crew, the time you're going to attempt any of the hesits, your platform of choice etc.. If you're by yourself, you can check for listings that want one or two more to start a heist.
The site also splits each heist into the different activities it has, so if you're stuck at the last bit of the Humane Lab heist, you don't have to do it all over again with a new crew. There's no messaging function on the site directly, so think of it as a bulletin board.
Check out LFH through here and make sure you bookmark our simple Heists guide for when you start playing.