DBD::Pg ... how would I format this prepare?

I need to do:

NOW() + '2 day'::interval

where 2 is a variable ...

if I do:

NOW() + '? day'::interval

it, of course, takes the ? as a literal ... so is there some way I can do 
this such that I can do the placeholder?

Thx

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email . scrappy@hub.org                              MSN . scrappy@hub.org
Yahoo . yscrappy               Skype: hub.org        ICQ . 7615664