Because I allways forget this, here ist how to do it.
Extract the Key and Cert
openssl pkcs12 -in pfxfile.pfx -nocerts -out keyfile.key -passin pass:pfxpassword -passout pass:newpassword
openssl pkcs12 -in pfxfile.pfx -clcerts -nokeys -out certfile.crt -passin pass:pfxpassword -passout pass:newpassword