Shell:

curl -n -F "file=@/home/user/foo" http://paste.xinu.at/   (binary safe)
cat file | curl -n -F "file=@-;filename=stdin" http://paste.xinu.at/   (binary safe)

Client:

Development (git): http://git.server-speed.net/users/flo/fb/
Latest release: http://paste.xinu.at/data/client/fb-0.9.1.tar.gz.
GPG sigs, older versions: http://paste.xinu.at/data/client/

If you want to use authentication (needed for deleting) add the following to your ~/.netrc:

machine paste.xinu.at password my_secret_password

Packages:
Arch Linux: pacman -S fb-client
Debian: http://paste.xinu.at/data/client/deb/
Slackware: http://paste.xinu.at/data/client/slackware/