I think You cannot paste the Infopath Forms into Outlook tasks But however
can email the forms to be filled out.
Here is a link which throws some light on Infopath and Outlook Plug ins http://blogs.msdn.com/rgregg/archive/2006/05/04/590552.aspx
InfoPath 2007 will integrate with Outlook, though I'm not certain if you can use it as an Outlook Task.
Please refer to Microsoft's web site for more information about InfoPath 2007's features.