The PrestaShop team have announced that they expect to release an RC version of PrestaShop 1.5 by mid-late February.
Defined as the RC (release candidate) version, this means that PrestaShop 1.5 will be ready for you to use on your store soon, but further improvements will be forthcoming as a final 'stable' release is developed.
Previous PrestaShop 1.5 release schedule
PrestaShop 1.5 has been under development since Summer 2011, and Mike Kranzler of the PrestaShop team had originally hoped for the PrestaShop 1.5 RC to be available by the end of November.
Unfortunately this wasn't to be, and the release timeline had to be reevaluated as the team decided to iron out a number of unforeseen bugs, and push out the best product possible.
Instead, the Alpha version (currently PrestaShop 18.104.22.168) was released, with a Beta for December-January, and finally the PrestaShop RC scheduled for February.
Get ready for PrestaShop 1.5
If you're a theme or module developer, it's suggested that you take a look at the PrestaShop 1.5 SVN to see what has changed and test your themes and modules ahead of the release.
Developers are also recommended to check PrestaShop's recently amended PrestaShop Themes & Modules Guidelines to ensure that your work will be compatible, and encourage 'best practices'.
If you're a merchant using PrestaShop 1.4 or lower, looking to upgrade to take advantage of PrestaShop 1.5's new features you can download the latest Alpha release from the PrestaShop downloads page (scroll to the bottom) and you test that your store works with PrestaShop 1.5.
As the PrestaShop team or finishing off 1.5, now would be a great time to report any bugs that you may find in the PrestaShop 1.5 Alpha to the development team.
You can do this on the official bug tracker, PrestaShop Forge.
Suggest new features
The PrestaShop team are also very active in the PrestaShop 1.5 sub-forum, and answering all sorts of questions and requests from the community.
There's a lot happening already, an the PrestaShop team have even recently asked what hooks the community would like to see in the new version. If you're a developer, this is a good chance to get something implemented that you feel has been missing.