What do you mean by list  picker? InfoPath supports dropdowns and
listboxes... but not a native *multiselect* listbox (I say "native" because
I have actually created InfoPath webform solutions with multi-select lists).

Yes, I'm looking for a multi-vlaue select utility. I recall SPS 2003
had a people picker  that was two multi-line list  boxes with Add,
Remove and Clear buttons between them.

What I'd like to do in InfoPath is make it work like the Content Type
Picker in MOSS like when you click on "Add from existing site content
types" in the Doc Library Settings.

If you are looking to use contact selector  in infopath  forms, please
take a look at the following link:
blogs.msdn.com/.../using-the-contact-
selector-control.aspx