This applies to those using the ever-pop­u­lar IM client, Adi­um.

Adi­um is a free instant mes­sag­ing appli­ca­tion for Mac OS X that can con­nect to AIM, MSN, Jab­ber, Yahoo, and more.

If you are in a sit­u­a­tion were you would need to back up your chat tran­scripts due to account migra­tion, or in need to do a clean instal­la­tion of your OS X machine, here’s where to start:

~/Library/Application Support/Adium 2.0/Users/Default/Logs

Note: This is cur­rent as of Leop­ard OS X 10.5.4, and Adi­um 2.x.