Smilie paks are still there. You just need to find people who have packaged their smilies as such. 2x pak files do not work on 3x though.
Upload the smilie image to forum/images/smilies
Bottom of the page click add multiple smilies
Smilies that have not yet been added appear at the top of the screen.
Enter a smilie code (ie the bit you type to get it to display)
Enter the Emotion (ie what it means)
Width and height if they are not already set
Choose whether it will be displayed on the posting page (ie to the right of the screen you write in)
Choose the smilie order (ie where it appears in the order of the smilies you have)
Tick the add box
If you cannot see the right side of the screen completely then you probably have a large smilie. You can fix this by clicking the triangle at the top left of the screen to close the admin menu and give you more width to play with.