From the maintenance section under system informaiton:
Gallery version = 2.2.6 core 1.2.0.8
PHP version = 5.2.6-2ubuntu4.6 apache2handler
However, the actual version is 2.3.1
version.dat from the data directory:
cat versions.dat
1.3.0.1
2.3.1
'doh
The system tab has an update button. :/