Need OpenSSL for this -
openssl genrsa 512/1024 www.mysite.com.key
openssl req -new -key www.mysite.com.key > www.mysite.com.csr
Enter country, state, locality, org name, org unit, comon name, and email when asked. Note: Common Name is www.mysite.com.
openssl -req -x509 -key www.mysite.com.key -in www.mysite.com.csr www.mysite.com.crt