Adding Group and Quick Add Groups to your custom webpart programmatically
SharePoint 2007 & 2010 development: How to remove a bad webpart from a page?
Problems with webpart after webpart is upgraded using Stsadm & Upgradesolution
Let the SharePoint Search web parts use an other Ranking Model
QueryStringPageViewer WebPart for Sharepoint – Mads Nissen
Inconvenient programmatically exporting Web Parts – Waldek Mastykarz
Programmatically Add ListViewWebPart with Customized View | Of Ones and Zeros
Stefan on SharePoint | Add Web Part to Page Programmatically
Quick Tip: Provisioning Web Parts to a Page – The SharePoint Guys – Site Home – MSDN Blogs
How to Add Web Parts to the Page Programmatically | Salaudeen Rajack’s SharePoint Diary
Presence Indicator:
sharepoint – Adding presence indicator to a custom web part – Stack Overflow
How to Display Presence Indicator in Custom Webparts « ahmedmadany
How to add Microsoft Office Communicator user presence icon to custom page/web part in SharePoint
Content Query Webpart – CQWP:
Formatting the Content Query Web Part and Removing HTML tags
SharePoint: Customize Content Query output with XSLT
How to: Display Custom Fields in a Content By Query Web Part
How to: Customize the Content By Query Web Part by Using Custom Properties
CQWP does not display list with custom datasheet
Extending Content Query Web Part with custom data – Waldek Mastykarz
Customizing the Content Query Web Part and Custom Item Styles