Basically all you do is freeze the chips with liquid nitrogen.

This does have a fairly significant impact on disk encryption software which is the most interesting part of the discovery. In a lot of the encryption programs the encryption key is stored as plain text in RAM. Once you get the key it is game over for your privacy/security. Vista’s Bitlocker, Apple’s FileVault and the open source TrueCrypt are all affected, amongst others, though the first two can be made immune to this attack by using another authentication method such as a smart card.

Edit: The Doctor has a better writeup.