The entire whatsnew is too long to list here. In summary:

MAMETesters Bugs Fixed
----------------------
tylz0122u5red [Zsolt Vasvari]
stadhero0122u3gre [Zsolt Vasvari]
stadhero0122u3ora [Zsolt Vasvari]
asterix_1055gre [couriersud]
blktiger37b15gre [couriersud]
newui0118u4ora [Atari Ace]
mpatrol0117u2gre [Aaron Giles]
realbrk0111u4gra [Brian Troha]
schmisr0111u5gra [Brian Troha, partial fix]
penbros0111u5gra [Brian Troha]
ninjakd2_0111u3gra [Nicola Salmoria]
mnight0102gre [Nicola Salmoria]
toki060gre [robiza, Corrado Tomaselli]

From the MAMEDEV news page:
"...Another dozen bugs squashed and bunch more fixes/improvements, spelled out in excruciating detail in the whatsnew.txt.

And no, I don’t think we’ll go up to 11, but there’s at least one more update expected before 0.123 is ready".

Get the Diff Intermediate Update and read the entire whatsnew here:
http://mamedev.org/updates.html

-Trebor