Another RSS alternative to Google Reader has popped up in beta, called NetNewsWire 4, but this one allows Mac users to add their Reader archives, store them locally for free and sync between Mac, iPhone and iPad.

NetNewsWire began as a standard newsreader for desktops in 2002. Black Pixel acquired the software in 2011, with the intention of re-launching it as an app for Mac and iOS. After the news that Google Reader plans to shutdown on 1 July, NetNewsWire faced the opportunity to add RSS functionality.

NetNewsWire 4 is now available in open beta, enabling the public to download it and provide Black Pixel with feedback. The new beta is a more refined version of NetNewsWire 4 Lite, the app that released in 2011, and it works with Mac OS X 10.7.3 or later.

The app isn’t as robust as other versions of NetNewsWire, but it's not a "lite version" and serves well as an RSS reader and aggregator. When asked if NetNewsWire was launching in time for Google Reader's cut off, Black Pixel founder Daniel Pasco told The Next Web, "absolutely". 

The beta is free, but the final software costs $10 when pre-ordered. It will go for $20 when it officially releases.

Read: Digg Reader public beta to open 26 June

Aside from NetNewsWire 4, stranded devotees of Google Reader will soon have other options with AOL Reader, Feedly, BlogLovin and Digg, among others. Digg confirmed earlier this month that its new RSS service, called Digg Reader, which uses the same API as Google Reader, will launch as a public beta 26 June