Microsoft is taking a page from rival Salesforce.com’s book and is launching an online store for third-party applications and services that build on top of its Dynamics CRM and ERP products.

Microsoft is unveiling its new app store plans on the opening day of the Worldwide Partner Conference on July 12.

Microsoft officials also are announcing the final name for Dynamics CRM 5 will be Dynamics CRM 2011. CRM 2011 has been in private beta testing for a few months. A public beta of the product will be delivered in September 2010, the Softies said.

In a somewhat unusual move, Microsoft is planning to release the online version of its CRM 2011 product before it delivers the software-only version. Microsoft is still committing to release the online service version before the end of calendar 2010. Company officials are still declining to say exactly when the software version will be out, but from what I’m hearing, it sounds like Q1 2011 is the target.

The new Microsoft Dynamics Marketplace will be open for business in September 2010, company officials said today. Microsoft is calling the Marketplace “an online catalog” that “will streamline solution discovery for customers and, will provide an easy way for partners to market and distribute solutions to Microsoft Dynamics CRM and ERP customers.”

Up until now, Microsoft has guided customers looking for third-party add-ons for its CRM and ERP products to use its Solution Finder search tool. But that site isn’t a destination where customers can actually go download code and install it. The new marketplace will allow partners to post code that customers can buy and download.

Microsoft CRM rival Salesforce.com has been offering customers the ability to buy, download and install applications from its partners via its AppExchange store for years. Salesforce redesigned and streamlined AppExchange in 2009. There are currently more than 1,000 apps available via AppExchange.

Google launched a similar online app store, the Google Apps Marketplace, in March of this year. Google’s online app store, launched in conjunction with 50 partners, allows developers to create add-ons to Google Apps and allows users to find and buy those apps, add-ons and widgets via an online portal.

Microsoft is working on a new online app store for the Waindows Phone 7 platform, which will be launching this fall. According to a leaked slide deck, Microsoft also is looking to build an online app store for Windows 8, which is expected to launch alongside the operating system in late 2011/sometime in 2012 (depending on whose guesstimates you believe).