Using the -text option will give you the full breadth of information.
openssl x509 -text -in cert.pem
Other options will provide more targeted sets of data.
# who issued the cert?
openssl x509 -noout -in cert.pem -issuer
# to whom was it issued?
openssl x509 -noout -in cert.pem -subject
# for what dates is it valid?
openssl x509 -noout -in cert.pem -dates
# the above, all at once
openssl x509 -noout -in cert.pem -issuer -subject -dates
# what is its hash value?
openssl x509 -noout -in cert.pem -hash
# what is its MD5 fingerprint?
openssl x509 -noout -in cert.pem -fingerprint