On modern Ubuntu (or, generally, Debian-based) systems the installation process is cleanly straightforward:

sudo apt-get install python-pip python-dev
sudo pip install -U pip
sudo pip install -U tiddlywebwiki

On less recent Ubuntu systems, pip will not be available as a package. In that situation, setuptools will first need to be installed:

sudo apt-get install python-setuptools
sudo easy_install -U pip
sudo pip install -U setuptools
sudo pip install -U tiddlywebwiki

(it might be necessary to remove setuptools.egg-info and setuptools.pth in /usr/lib/python2.5/site-packages or the equivalent directory)

If Apache and mod_wsgi are to be used, libapache2-mod-wsgi should be installed (via apt-get) as well.