I would like to know what version of glibc will be used in later releases. Is that information available?
for package lists have a look at http://packages.ubuntu.com/.
at the moment for glibc this can be offered...
--> this means for now it can't be answered completely because a feature freeze is usually approximately 2 months before the release, so there might change something!
Ubuntu's "feature freeze" is usually a couple of months before release. Until that happens, the versions of packages in the development version of the next release will continue to change,staying roughly in sync with Debian's Testing release (or is it Unstable? Note to self:check and edit this answer).
That said, it is rare in the extreme for package versions to go down, especially at this point in the development cycle.
Right now, therefore, there is no way to know what version of a given package will be in the final release - but you can establish a lower bound.