I have iTunes 9.0.1 running under OS X 10.6.1 on two computers - A Mac Pro and a Mac Mini.

On the Mac-Pro, I get the expected behavior when i search directly in song lists.

Click on Music under LIBRARY

Select All (Genres) All (Artists) All (Albums) in the iTunes 8 style top browser

Click on the 'Name column' to sort songs alphabetically

Then start typing, for instance "Hall", iTunes jumps directly to the first song that starts with 'Hall', in my case "Halleluja' by Charlie Parker.

On the Mac-Mini when I replicate the above, nothing happens. It looks like the Mac does not respond at all to my typing. Searching the song using the search pane top-right obviously works, but there i need to first select 'song' as search criterium and after typing 'Hall" i get all songs containing 'Hall' which in my case is 41 songs.