Ok - So I have a shared documents library - and like many posts before me I would like to make the default tab on the ribbon a custom tab that I have made. Can someone tell me how to edit the URL using code without having to manually type in the url aspx?InitialRibbonID=Ribbon.CustomTabExample...... PLEASE
Try manipulating the InitialTabId of the SPRibbon object. Set the attribute value to the id to your tab and then it will be selected when the document library loads.
Here is a sample example: http://kmukesh.wordpress.com/2011/05/18/how-to-create-custom-site-ribbon-tab-with-buttons/