Excellent, thanks Jens.
I did read that document, except the bit on troubleshooting at the bottom - which is exactly what I was missing, and you were right - bad lib path was the problem.
For anyone who's interested, below is the full set of commands I used to build and get it running - assumes nothing installed except a clean, out of the box Ubuntu 9.10. I haven't really tested it's all working yet, but certainly fires up and looks like it's all there.
Thanks again,
Brad
sudo apt-get install libgtk2.0-dev libwxgtk2.8-0 libwxgtk2.8-dev wx-common subversion autoconf automake libtool gobjc++
mkdir codeblocks
cd codeblocks
svn checkout svn://svn.berlios.de/codeblocks/trunk
cd trunk
export ACLOCAL_FLAGS="-I `wx-config --prefix`/share/aclocal"
./bootstrap
./configure --with-contrib-plugins=all
make
sudo make install
echo /usr/local/lib | sudo tee -a /etc/ld.so.conf
sudo ldconfig
codeblocks