Trillian offers a host of features including encryption (Meebo does too) that can make your IMs more secure, even from your IT department. Although we prefer Meebo since it doesn’t require a download, you might have to especially if you are traveling to a not-so-safe destination or will be behind the Great Firewall of China.
If you are already using Trillian version 3.1 or older, make sure you update to the latest version. A critical vulnerability was discovered in the software that could allow an attacker to takeover (Windows) machines. Check to see you are using version 3.1.5.0 at least.
Thanks Peaceluvbug!