I converted to Judaism in 2010 and have been studying Hebrew on and off since.  Here are some useful sites and books on  Judaism in general, Jewish conversion, and haredi culture. Hebrew gets its own page.

Judaism, generally
The Jewish Bible: Tanakh: The Holy Scriptures — The New JPS Translation According to the Traditional Hebrew Text: Torah * Nevi’im * Kethuvim – not the most scholarly, but probably the most accessible edition.

Jewish Literacy Revised Ed: The Most Important Things to Know About the Jewish Religion, Its People, and Its History – among the best books for someone just starting to grapple with Jewish life.

Jewish Holidays and Festivals – There are many, many criticism of Chabad, but their website is accessible and informative for everyone. This is their page on the holidays.

Jewish Conversion

JDiscover – JDiscover’s Gateways to Judaism class was my introduction to Jewish learning.  Highly recommended if you live in the Washington, DC area.

Interesting Gers — my series on interesting people who’ve converted to Judaism.

The Haredim 

Failedmessiah – A controversial, and extremely informative, blog on judaism in general and ultra orthodox judaism in particular.