Because the 1.1.3 firmware takes up more space on the system partition than 1.1.2, you can quickly start running into disk space problems.

To solve these problems (like the Installer jumping to Springboard while installing a package), you can move your applications folder to the media partition like this:

Connect to your iPhone using SSH and issue the following commands:

cp -r /Applications /private/var/
rm -r /Applications
ln -s /private/var/Applications /
chmod +s /Applications/

Close your SSH session.

You should now be able to run all applications and install new ones.