EDIT: There are some noteworthy differences between the two. 3.0 has a no endorsements clause, and it introduces the concept of a "Creative Commons Compatible License", a third-party license approved by CC as "essentially equivalent" (none are approved yet). The generic license was renamed to be the US license, and they made a new "unported" license (linked above) to fulfill a similar role. 3.0 is also approved as free by Debian. CC has a article and blog entry with more info.
Good catch, I updated it to refer to 2.5 for consistency if nothing else. Not sure if the minor tweaks of 3.0 over 2.5 are particularly relevant to us, or not.
edit: as of yesterday, we re-licensed under cc-by-sa-3.0.