I've wanted something like this for the longest time! I've found when surfing, chatting online, working with email that I keep stumbling on loads of links to interesting stuff I wanna read - but just not right now - later.
I've often kept open loads of FireFox windows for stuff I should read soon (which then means I struggle to find what I am currently reading/working on from stuff I wanna read later). Then I've been through phases of cutting and pasting interesting articles into files/wikis for later. I've always felt this was sucky and wanted a nicer solution.
Now there's latrz and I confess to being totally hooked already :).
Basically if I'm on a page I know I wanna read, I click the Read Latrz bookmarket, then close the browser or carry on doing what I'm doing. Then when I've time I just click on the latrz site to read whatever takes my fancy, then mark it as read when I'm done to remove it from my reading list.
Go on, give it a try or subscribe to the Latrz Blog, you know you want to :)