When I start my Natty computer and open a terminal, it takes like 20 seconds before the prompt show up. I did not change my .bashrc lately, it appears that this started after the upgrade to 11.04
try moveing your .bashrc to some backup file ie: MyOriginal.bashrc and see if the problem still happens with no .bashrc at all.
If the problem still occurs with no .bashrc that would point to some system issue, another test would be to create a new user, and see if the problem happens for them.
If it does follow the .bashrc you may want to paste the .bashrc here