If you are using Firefox on your PC and don't have issue on it with logging, you can copy PC's cookies.sqilte into N900 (location /home/user/.mozilla/microb/). On my N900 I'm using key3.db, signons.sqlite and cookies.sqilte from my PC and this way I have the same passwords and cookie settings on both, which is really great. Also PC's Firefox enables you to remove individual cookies, passwords etc.