KDevelop 4 is now available in lucid-backports for users of the newly released 10.04 LTS.

Enable "Unsupported Updates" in your software repositories and install "kdevelop".

KDevelop 4 Beta 9 is out.

Users of our latest development release, Lucid, can get packages from our Beta PPA.

To update, use the Software Repository Guide to add the following repository to your software sources list:
ppa:kubuntu-ppa/beta

then install kdevelop