After my previous failed attempt at installing Carbide C++ to allow me to develop stuff for Nokia E71 (i.e. Symbian), recently I have been digging up the internet on information on how to develop directly in Linux.
After much digging and lots and lots of confusion, I actually managed to find some useful information which allowed me to install a cross compiler and the C++ SDK for my phone (S60 3rd Edition Feature Pack 1) on my MSI PR200 laptop which runs Debian Lenny (amd64). The compiler was built from source and its build arch is x86_64 linux, so it should be able to be a little bit faster than the precompiled binaries for i686.
The key of the solution was the GnuPoc project and the fork that offers support for platforms newer than S60 v2 which is avilable at:
Besides the GnuPoc download, you'll need to install the appropriate toolchain and compiler:
EKA1 + a modfied gcc release - for S60 v1 and v2
EKA2 + CodeSourcery's GCC (I chose the source variant) - for S60 v3 or newer and UIQ
The instruction on Martin's page are really good, so I won't repeat them here.
After this, there's the non-free part, the SDK installation which needs to be downloaded from forum.nokia.com (you need an account on forum nokia, but the download is free of charge). The installation procedure is also explained on Matrin's page and they work properly (at least they worked for me).
By the way, there are two variants of the SDKs: a full SDK (Java, C++) and one only for C++. The instructions refer to the C++ version, but I don't know if they'd work with the full version.
I did everything until this point and I haven't completed and/or tested if things work, but I'll do it and update the information.
 actually I needed a tool chain, but having a graphical IDE was looking really good