to run the most recent libsecondlife release you need to have at least mono 1.9 installed. the following step-by-step recipe applies to a ubuntu 7.10 system and you should be root:

installing pre-reqs

apt-get install build-essential bison gawk
apt-get install libglib2.0-dev
apt-get install libpng12-dev libx11-dev libfontconfig1-dev 
apt-get install libfreetype6-dev libjpeg62-dev libtiff4-dev 
apt-get install libungif4-dev libexif-dev libcairo2-dev
apt-get install libpango1.0-dev libgtk2.0-dev libglade2-dev
apt-get install libgnome2-dev libgnomecanvas2-dev libgnomeui-dev
apt-get install libgnomeprint2.2-dev libgnomeprintui2.2-dev 
apt-get install libpanel-applet2-dev libgtksourceview-dev
apt-get install libgtkhtml3.14-dev

installing libgdiplus

wget http://go-mono.com/sources/libgdiplus/libgdiplus-1.9.tar.bz2
tar xvf libgdiplus-1.9.tar.bz2
cd libgdiplus-1.9
./configure --prefix=/usr/local
make
make install

installing mono

wget http://go-mono.com/sources/mono/mono-1.9.tar.bz2
tar xvf mono-1.9.tar.bz2 
cd mono-1.9
./configure --prefix=/usr/local
make
make install

installing nant

wget http://switch.dl.sourceforge.net/sourceforge/nant/nant-0.86-beta1-src.tar.gz
tar xvf nant-0.86-beta1-src.tar.gz
cd nant-0.86-beta1
make install prefix=/usr/local

you now have the base setup, which is sufficient for building and running libsecondlife and opensim. the following packages are add-ons that are nice-to-have but not necessary-to-have. i do recommend installing the monodoc & mono-tools stuff, however — it makes live easier :-)

gtk-sharp

wget http://go-mono.com/sources/gtk-sharp210/gtk-sharp-2.10.4.tar.bz2
tar xvf gtk-sharp-2.10.4.tar.bz2
cd gtk-sharp-2.10.4
./configure --prefix=/usr/local
make
make install

gnome-sharp

wget http://go-mono.com/sources/gnome-sharp2/gnome-sharp-2.16.1.tar.gz
tar xvf gnome-sharp-2.16.1.tar.gz
cd gnome-sharp-2.16.1
./configure --prefix=/usr/local
make
make install

gtksourceview-sharp

wget http://go-mono.com/sources/gtksourceview-sharp2/gtksourceview-sharp-2.0-0.12.tar.bz2
tar xvf gtksourceview-sharp-2.0-0.12.tar.bz2
cd gtksourceview-sharp-2.0-0.12
./configure --prefix=/usr/local
make
make install

monodoc & mono-tools

to get the monodoc C# documentation viewer (recommended!) we need to install the monodoc package and the mono-tools package. monodoc itself needs to be installed inside the mono-1.9 source directory¹ from above.

cd mono-1.9 # this is the source directory from the above
wget  http://go-mono.com/sources/monodoc/monodoc-1.9.zip
unzip monodoc-1.9.zip
cd monodoc-1.9
./configure --prefix=/usr/local
make
make install
cd ../..

next, install mono-tools:

wget http://go-mono.com/sources/mono-tools/mono-tools-1.9.tar.bz2
tar xvf mono-tools-1.9.tar.bz2
cd mono-tools-1.9
./configure --prefix=/usr/local
make
make install

configure will mumble about gecko-sharp.dll not being build, that’s ok, just ignore it.