pip install requirements

pip install requirements

(ambiente_app_contatos)fabio@fabio-vbox:~/app_contatos_django$ pip install -r requirements.txt 
Requirement already satisfied (use --upgrade to upgrade): Django==1.3.1 in 
/home/fabio/.virtualenv/ambiente_app_contatos/lib/python2.7/site-packages (from -r requirements.txt (line 1))
Requirement already satisfied (use --upgrade to upgrade): wsgiref==0.1.2 in 
/usr/lib/python2.7 (from -r requirements.txt (line 2))