] Open Smiler, then scroll through the over 2,500 available
] smileys. When you found one you want, click it and the
] smiley code will appear in the text box below. Click the
] Copy to Clipboard button, then switch to your AIM chat
] window. To paste the smiley into your chat window, Use
] Edit / Paste or the keyboard shortcut CTRL-V.

This uses the same "click on the link and drag it up to your browser's 'Links' menu to make a button" system that Memestreams does. I thought it was pretty spiffy, and gives you access to literally thousands of different "emoticon" graphics that can be pasted into an IM window. I haven't tested it yet to see if it works with Trillian, but it looks like it's worth a shot!

AIM Smileys - BigBlueBall.com