You can find information about this in the Microsoft CRM SDK Client Programming Guide.
The latest online help update includes this information:
Microsoft Dynamics CRM includes features to enable other applications to be integrated into Microsoft Dynamics CRM so that users can access Web-based applications. The primary client-extension features are:
- IFRAMES ( Windowless inline floating frames that are typically used for including Web pages in forms. Examples of Web pages that can be included are a page from a SharePoint site, a section of HTML such as a button, or a custom application.) provide a way to display a Web page or Web application within a Microsoft Dynamics CRM form. IFRAMES are added using the tools used to edit an entity form. More information: Edit Entity Forms
- Site Map ( An XML representation of the structure of the Navigation Pane in Microsoft Dynamics CRM, including the areas, groups, and subareas where entities are displayed, and the privileges associated with each subarea. ) provides a way to include an application that will appear in the main pane of the Microsoft Dynamics CRM application. It can also be used to fine tune the way areas and groups are displayed in the Navigation Pane. You can use Site Map to change the labels displayed for areas in the Navigation Pane. More information: SiteMap (Microsoft Dynamics CRM Software Development Kit)
- Use ISV.Config ( An XML configuration document used to update the navigation structure of Microsoft Dynamics CRM, including adding custom buttons, tabs, and menus to entity forms. ) to include custom menu items and button controls within Microsoft Dynamics CRM. ISV.Config can also be used to add additional navigation items within entity forms. Each navigation item is configured with either a URL or some client-side script to perform an action when the navigation item is clicked. More information: ISV.Config (Microsoft Dynamics CRM Software Development Kit)
- Each Microsoft Dynamics CRM entity form has a specific URL that can be used to create a new record or open an existing record. Other applications, such as SharePoint, can be configured to allow Microsoft Dynamics CRM users to interact with Microsoft Dynamics CRM data from other applications. More information: Microsoft Dynamics CRM Software Development Kit