DEB files are compressed data files, you can expand them by following the next steps:
1. Open Terminal and cd to the directory of the deb file
2. Type: ar vx filename.deb

To install them on your iPhone follow the next steps:
1. SFTP or SCP your deb file into /tmp
2. SSH into your iPhone with Terminal and type: dpkg -i /tmp/filename.deb

Or you can use Cydia to install them immediately onto you iphone