I have two sheets - one with rows A-I and ID numbers 1-9 (like this:
http://img.photobucket.com/albums/v2...ton/excel1.jpg ), another
with the same ID numbers 1-9, but instead of the lettered row, one with
various colors (like this:
http://img.photobucket.com/albums/v2...ton/excel2.jpg ). I have
a filter on the second sheet so I can sort by color to see all the IDs
that have that color (IE red has 1,3,4,8), and vice versa with the
numbers. How would I set it up so that I could sort the second sheet by
the various colors and have Excel simultaneously sort the first sheet
in the same way?

In the first sheet, next to your data, add the function:
=vlookup(B2, Sheet2!$A$2:$B$10,2,0)

You can then sort by column C:C

HTH
Kostis Vezerides