There seems to be no Debian packages for XOTcl. The installation instruction of XOTcl mentioned TCL sources are a must. Many people will put-off installation because of these points.

Things are not that complex.Here is a instruction to get it going.

Actually TCL headers are required, not full source files.

Debian packages required - tcl package and tcl-dev package. tcl-dev is required if you want any C based extension for Tcl.

In my case, 
 apt-get install tcl8.4
 apt-get install tcl8.4-dev

The required packages for compiling C code (someone mention that. I assume they are present).

Get the source code from xotcl website.

let us say you had downloaded xotcl_xx.tar.gz to '/var/downloads'
 
cd /var/downloads . tar xvzf xotcl_xx.tar.gz
 
cd /var/downloads/xotclxxx
./configure --with-actiweb --with-tcl=/usr/lib/tcl8.4
make

Now you will have libxotclxxx.so in /var/downloads/xotclxxx

Now copy that (*.so) into you desired directory and play with xotcl.
tclsh
load ./libxotclxxx.so
namespace import xotcl::*
object junk
junk destroy

for more info
[xotcl for prototying]