For this code in Framework 1.1 :  Page.RegisterStartupScript("myScript", myScript), I am getting error in VS2010.

Public Overridable Sub RegisterStartupScript(key As String, script As String)' is obsolete :

In order to fix this in Framework 2010, what is the best way?

ClientScript.RegisterStartupScript(Page.GetType(), "myScript", myScript) or
ClientScript.RegisterStartupScript(Me.GetType(), "myScript", myScript)

The Page.RegisterStartupScript is now obsolute, you need to use the other method
ClientScriptManager.RegisterStartupScript Method

For 2010 you need to use the ClientScriptManager.RegisterStartupScript Method only