Jaunty Alpha 5 is scheduled for this Thursday, February 26, so the milestone "freeze" is now in effect. Please take care that any packages you upload to main between now and the Alpha 5 release will help us in the goal of a high quality and timely alpha, and hold any disruptive or unnecessary uploads until after the alpha is out. Again, this means the primary focus should be on resolving these bugs: https://bugs.launchpad.net/ubuntu/jaunty/+bugs?field.milestone=2213
The number of bugs targeted to this milestone as blockers is small, but there's plenty of other work to be done in getting the archive in a consistent state so that we don't have uninstallable packages for the alpha-5 milestone: https://wiki.ubuntu.com/UbuntuDevelopment/PackageArchive#Consistency
Remember that this is a "soft" freeze, so you are each responsible for making sure your uploads are appropriate - Launchpad will not be your safety net.
Packages that are not seeded on the CDs (i.e., most packages in universe, with the exception of UbuntuStudio, Xubuntu, and Mythbuntu packages) may be uploaded as usual.