It's a little weird (to me at least), but upvoting stories in HN is considered 'saving' them. You can view all your saved stories from your profile page under the link 'saved stories'.

You can also just go to: http://news.ycombinator.com/saved?id=jholman

There is also this to download those 'saved' links:

https://github.com/bsandrow/hn-profile

Reminder Bear, created by a fellow HNer, works pretty well for this - http://app.reminderbear.com/

if only there were a way to save and share urls using some sort of online service.

Bookmark the page in your browser?

I use instapaper for stuff like that.