Hello
Infopath Forms created in 2007 can be saved to be compatible to 2003
Please read the link below for more detail
http://www.infopathdev.com/blogs/david/archive/2007/05/24/Developing-IP2003_2D00
_compatible-forms-in-IP2007.aspx
I hope it will help you.

Signature
Kalyan G Reddy - INFOPATH MVP 2007
http://www.ggktech.com
> I have Infopath 2003 installed and am trying to open some Infopath templates
> that someone else has created (possibly in 2007-not sure) and I am receiving
[quoted text clipped - 3 lines]
> Does this mean I need to download Infopath 2007 to be able to open these
> files?