The Audacious developers have removed support for Last.FM / Scrobbler in the most recent version. See http://boards.audacious-media-player...=3&t=112&p=408 for why.

I've successfully built the 2.2 plugin against 2.3 on Ubuntu Lucid (which just updated to 2.3). Here's (roughly) what I did.

Code:
sudo aptitude install libcurl4-dev

wget http://distfiles.atheme.org/audacious-plugins-2.2.tgz

tar -zxvf audacious-plugins-2.2.tgz

cd audacious-plugins-2.2

./configure --enable-dependency-tracking --disable-esd --disable-pulse \
--disable-coreaudio --disable-icecast --disable-dockalbumart --disable-altivec \
--disable-sse2 --disable-mp3 --disable-libmadtest --disable-rocklight \
--disable-lirc --disable-evdevplug --disable-hotkey --disable-gnomeshortcuts \
--disable-statusicon --disable-aosd --disable-aosd-xcomp --disable-adplug \
--disable-vorbis --disable-flacng --disable-libFLACtest --disable-wavpack \
--disable-aac --disable-sndfile --disable-modplug --disable-ffaudio \
--disable-jack --disable-sid --disable-oss --disable-oss4 --disable-alsa \
--disable-amidiplug --disable-amidiplug-alsa --disable-amidiplug-flsyn \
--disable-amidiplug-dummy --disable-cdaudio --disable-streambrowser \
--enable-scrobbler --enable-lastfm --disable-neon --disable-mms \
--disable-mtp_up --disable-bluetooth --disable-paranormal --disable-xspf \
--disable-xmltest --disable-cue --disable-projectm --disable-projectm-1.0 \
--disable-filewriter --disable-filewriter_mp3 --disable-filewriter_vorbis \
--disable-filewriter_flac --disable-bs2b


cd src/scrobbler/

make

sudo make install

cd ../lastfm/

make

sudo make install
It's definitely scrobbling, beyond that I haven't bothered figuring out what's broken or how one would play the last.fm radio (I never use it, so I don't care). I briefly looked into making a package but it's too much of a hassle, I'm assuming either someone else will or people will just move on to another player.

Hope this helps and that someone else will slog through the mess of making it into a package.