Repackaging Tomcat 6 from Squeeze in Lenny (as discussed in build_a_package_from_squeeze) is possible but a MAJOR pain in the ass. I did it just once and will not be doing it again. Instead I find it easier to install the binary packages from Squeeze directly in Lenny as follows:

Add the squeeze repository to your /etc/apt/sources.list

# Repository for Squeeze, to get Tomcat6
deb http://ftp.de.debian.org/debian/ squeeze main contrib non-free

Edit /etc/apt/preferences to include the following:

    Package: tomcat6,tomcat6-admin,tomcat6-common,libtomcat6-java,libservlet2.5-java
    Pin: release o=Debian,a=testing
    Pin-Priority: 990

Update sources

    # apt-get update

Upgrade

    # apt-get upgrade

Install

    # apt-get install -t testing tomcat6

You may want also to install the tomcat manager

    # apt-get install -t testing tomcat6-admin

Create new users/roles for tomcat manager

    # vi /etc/tomcat6/tomcat-users.xml

NOTE: Webapp is located at /var/lib/tomcat6/webapp