Here are some great links for learning Chinese.

Chinese Pod My favorite way to learn spoken Mandarin, say "hi" to Jenny and Ken for me

How to Bargain

BBC Real Chinese

Most Common Characters

Traditional/Simplified Conversion Tool

Pinyin

Learn Chinese

Chinese Idioms

Food

Numbers

Audio Chinese

Bo Po Mo Fo

Fonts

Tone Drill

Watch Chinese TV Online

This lask link in particularly helpful.  This software has the best dictionary i've seen.  It allows you to put in pinyin, chinese characters, or english and get the definition.  It even pronounces it for you!  I recommend enabling Asian language support for Microsoft Windows.  Follow these steps:  Start->  Control Panel->  Date, Time, Language, and Regional Options->  Regional and Language Options->  Languages->  check the box marked Install Files for East Asian Languages-> click OK

Chinese Practice