While a flood of dedicated apps have appeared on mobile devices for reading articles you've saved, desktop operating systems have mostly gone without. The newly renamed (and free) Read Later app — formerly ReadNow — from Michael Schneider acts as a desktop client for your Instapaper and Read It Later accounts. It's a pretty straightforward concept: the fullscreen reading app syncs with your online reading queue services, and supports your list or archives, liked articles, and tags. It's also got support for saving articles to services like Evernote, bit.ly, Twitter, Pinboard, and Delicious. Note: only Instapaper Pro users can use the app; regular Instapaper users will have to pay $1 a month.
All of the actions you make when offline will be pushed to Instapaper or Read It Later when you gain a connection again, and drag and drop functionality makes managing multiple folders much easier than on a mobile device. The app's design looks awfully similar to the Reeder RSS app with Read Later also using three columns, action buttons for each article on the top right, and the site's favicon on the far right edge. Still, it offers offline reading and several tools for tweaking display, including line height, fonts, and several styles.
Pro tip: don't turn Growl support on before refreshing, or your screen is going to get flooded with hundreds of successful sync alerts.