Apple today quietly updated the default processor speeds on new Intel Mac minis, at no extra cost. Of note the Mac mini did not receive an upgrade to the Core 2 processors but continues to use Yonah chips.
The base model now features a 1.66Ghz Intel Core Duo processor (formerly a 1.5Ghz Core Solo) and retains its £399/$599 pricetag.
The higher specification model has had its 1.66Ghz Core Duo processor upgraded to 1.83Ghz and also retains its pricing at £529/$799.
World of Apple previously reported on speculation that Mac minis could be receiving an update soon.
[Update] With the addition of today's Mac mini update Apple has added a 160GB hard drive upgrade as a Build-to-Order option, although the upgrade pushes back deliveries by 1-2 weeks.