This is so great!
You have to check out this ICD coding reference.
These techno-angels have created a free database of ICD-9 codes, including those for 2013.
We've taken the official 2006-2013 ICD-9-CM and HCPCS coding books and added 5.3+ million hyperlinks between codes. Combine that with a Google-powered search engine, drill-down navigation system and instant coding notes and it's easier than ever to quickly find the medical coding information you need.
They're supported by Google Adsense, so it's totally free to use. The'll even convert ICD-9 codes to ICD-10 codes. And they were happy to have me link to their site. You gotta love these guys.
What would be super-great is if they wrote some code to convert DSM-IV codes to ICD-9 codes. Maybe I'll write to them about it.
And for future reference, I've added a link to their site under "Useful Links", to the right.