Well, offers here a list of sites where you can find various information about applications RIA and the general content of these sites.

In Portuguese / Brazilian:

http://www.riapt.org/ Community of Portuguese Ria's
http://www.vedovelli.com.br/ Site with some screecast's.
http://www.flexbrasil.org official site from the list of flex-brasil yahoo
http://www.igorcosta.com/blog/ Site of the founder of Flex-Brazil
http://www.wendelmaques.com.br/ Site on Ajax, extjs, air and flex.
http://leonardofranca.com.br/index.php/pt/ site that talks about everything a little bit about Ria's
http://blog.zellen.com.br/ Site dedicated to Ria's

In English / Other:

http://www.flex.org official site of Flex
http://www.amfphp.com Library php / mysql / sql to communicate with the flex / flash
http://www.person13.com/wordpress/ Talk a little bit of everything ...
http://flexed.wordpress.com / Flex and ActionScript
http://labs.adobe.com/technologies/air/ Adobe Air
http://labs.adobe.com/technologies/flex/ Adobe Flex
http://silverlight.net/ Microsoft's Silverlight
http://www.microsoft.com/expression/ Around the world Silverlight / Expression

http://www.thefreecountry.com/webmaster/ajax.shtml Ajax frameworks and tutorials

Adobe Flex Explorers
A list of shows that explore much of what you can do with Flex:

http://examples.adobe.com/flex2/consulting/styleexplorer/Flex2StyleExplorer.html - Style Explorer (manufacturer seo de)
http://www.maclema.com/content/sek/ Style Explorer (the same but with support KULLER - http://kuller.adobe.com -)
http://demo.quietlyscheming.com/ChartSampler/app.html (Charts Explorer, operator of graphics / statistics)
http://examples.adobe.com/flex2/inproduct/sdk/explorer/explorer.html (Demonstration of components drag & drop)
http://www.merhl.com/flex2_samples/filterExplorer/ (Filter Explorer, fade, alpha, glow, distorta)
http://www.3gcomm.fr/Flex/PrimitiveExplorer/Flex2PrimitiveExplorer.html (Primitive Explorer, graphics via actionscript, properties)
http://flexapps.macromedia.com/flex15/explorer/explorer.mxml?versionChecked=true (Samples Explorer, examples with source code)
http://www.madeinflex.com/img/entries/2007/05/customeasingexplorer.html (Custom Easing Function Explorer, allows custom effects via actionscript)

They must have the Flash Player 9 update (available here: http://labs.adobe.com/downloads/flashplayer9.html) If you can not see.

I hope that you will be useful:)