I read quite a lot of articles off HN, I usually have all 8 tabs in my iPhone full of sites sites I've read but want to save. Often I will email myself the link, however then it gets caught up in my inbox and not the best way to search.

Is there an app/site where I save these urls, tag them and possibly even take a image/pdf of the site, so if it goes down or offline reading I can still access the content.

Something like Delicious but it doesn't seem to do the offline part.

What do you use to keep track of interesting links?