David Leedy has come through one more time for the Lotus community, he has now launched XPagesCheatsheet.com which will provide not only the printable cheat-sheet, but also a downloadable demo database. This db includes some great examples, including how to do a multiple select of items from a repeat control.
Also check out Notesin9.com if you have not previously, great content with an easy to learn atmosphere.
This is actually very simple to do.
Step 1. Create a standard combobox on an xpage.
Step 2. Create values for that combobox.
Step 3. On the dojo property panel set the dojotype to dijit.form.ComboBox.
Now you are finished, you will have drop down capabilities as well as type ahead and you can type in a new value as well.