Totally wrong, Freenode recently transitioned to a new IRC daemon (..January) and with that they introduced SSL support, on port 7000/7070 and the more common 6697.
http://freenode.net/faq.shtml#sslaccess
http://blog.freenode.net/2010/01/fre...-live-freenode
As for the OP, verifying the SSL certificate is indeed a good step, but it's optional, you can obtain the certificate on their website or by retrieving it using openssl.. once you have it set ssl_capath directly to the file, storing it in ~/.irssi/certs is as good of place as any.