ITA stands for Intention To Adopt, and is one of the states that a bug against the wnpp package can be in.
When a maintainer gives up a Debian package, either through filing
an ?O or ?RFA bug someone else can say they will maintain the
package. They do this by retitling the bug to begin with
set themselves as owner. They then prepare a version of the package
with themselves as Maintainer, and upload it.
The current list of packages being adopted can be seen at http://www.debian.org/devel/wnpp/being_adopted. More information on what to do to adopt a package can be seen at http://www.debian.org/devel/wnpp/#l3.