Creating Custom Buttons in CRM Toolbars

To Create Custom Button in the CRM 4.0 Toolbar, you need to export the ISV.config file and under Entities node you need to add the following XML for your targeted entity i.e. new_project

<Entity name="new_project">
<ToolBar ValidForCreate="0" ValidForUpdate="1">
<Button Icon="/_imgs/ico_18_debug.gif" JavaScript="ConvertToProject();">
<Titles>
<Title LCID="1033" Text="Convert To Project" />
</Titles>
<ToolTips>
<ToolTip LCID="1033" Text="Convert To Project" />
</ToolTips>
</Button>
<ToolBarSpacer />
</ToolBar>
</Entity>


where ConvertToProject(); is the javascript function you want to execute on the button click and it should be defined in your form onload

One more thing, you need to add the clients in system setting > Customization tab  to see the samples from ISV.

enjoy :)