First I recommend you run ./configure --help and check whether any of the options will be useful to you.
Then it's just a matter of running the usual:
./configure make make install
make install should normally be performed as root, but it's recommended to do the first two stages as a normal user in a directory you own.
It's recommended that you include INN's binaries in your
PATH before running configure, if they're not in one of the
standard branches or in one of
/var/lib/news/bin. This will help newsstar decide the
PATH variable to use at run-time.