Where to start with Google Reader as an API?

I want to build a widget for WordPress that simultaneously displays my latest Google Reader items on the front page and allows for management from behind the WordPress dashboard. I can already add my "shared" items using code I've found in various Google searches, but that's not exact开发者_StackOverflow中文版ly what I'm looking for.

I like the functionality of the Google Reader widget in iGoogle, and I want to replicate that on the WordPress dashboard and build a read-only version for the WordPress front-end. Where do I start in the API (public or 'unofficial') to get this built?

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I've found some limited documentation regarding authentication protocols, but I've been unable to implement anything. I can parse a URL to authenticate and get an SSID that works when directly placed in a browser, but both GET and POST requests fail via PHP, so I can't get any further than that.

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I've converted the first few steps of Martin Doms' C# tutorial into PHP for anyone who's interested in doing this on their own site.

Here's a nice 3-step tutorial: http://blog.martindoms.com/2009/08/15/using-the-google-reader-api-part-1/

If you're having problems from PHP, then I think you should post the PHP code to see where it's failing. These steps should work flawlessly.

I can add some extra resources, especially the ones that resemble the most a structured documentation for this unofficial API:

• http://code.google.com/p/pyrfeed/wiki/GoogleReaderAPI - Very good and structured API documentation.
• http://blog.martindoms.com/2009/10/16/using-the-google-reader-api-part-2 - (Already referred above) Also a well structured API documentation, in 3 parts. Contains some details not seen elsewhere.
• http://www.chrisdadswell.co.uk/android-coding-example-authenticating-clientlogin-google-reader-api/ - Good resource for coding examples and API documentation
• http://groups.google.com/group/fougrapi/ - 'Official' group for the unofficial Google Reader API. Lots of advanced questions, often answered by Google developers. Not good for structured documentation though...

Hope it helps!

Following up on EAMann his PHP class is here http://code.google.com/p/greader-library/source/browse/trunk/greader.class.php?r=4. I got it working last night. Thank you Eric, I will be adding to your library.