Open a terminal. Log in as root to install wine and cabextract:

emerge wine cabextract

Logout and install IEs 4 Linux with your normal user account:

wget http://www.tatanka.com.br/ies4linux/downloads/ies4linux-latest.tar.gz
tar zxvf ies4linux-latest.tar.gz
cd ies4linux-*
./ies4linux