On my Debian Squeeze I get the following:

    $ curl --version
    curl 7.21.0 (x86_64-pc-linux-gnu) libcurl/7.21.0 OpenSSL/0.9.8o zlib/1.2.3.4 libidn/1.15 libssh2/1.2.6
    Protocols: dict file ftp ftps http https imap imaps ldap ldaps pop3 pop3s rtsp scp sftp smtp smtps telnet tftp 
    Features: GSS-Negotiate IDN IPv6 Largefile NTLM SSL libz

Looks pretty impressive.