What are pros and cons of using SSL self-signed certificates?
Take a look at what other people have written about it.For applications such as webmail access for your employees, web service calls between your servers, etc., a self signed certificate can work just fine.
As far as the SSL encryption goes, a self signed certificate is just as secure as a cert signed by Verisign.
If you have a small (or large) organisation, you may have several different services that need encrypting.
You'll need one for every website (e.g. www, intranet, wiki, webmail) and you'd need one for mail services. This soon mounts up to quite a few certificates.
Because you have a limited number of users, it becomes possible to generate your own root CA and distribute the public key to your users. This has the advantages of being free and can be used for trusting servers, but at the expense of requiring your users to import your root certificate.