The method to carry out either task has changed a bit from previous versions of iOS, but it's still just as easy.
When in a conversation in the Messages app and you want to delete or forward a message that was sent to you, you simply tap and hold on the message bubble until the options "Copy" and "More..." come up.
Tapping on "More..." will give you the option to forward or delete the message, using the buttons located at the bottom of the screen. You can select multiple messages using the bubbles on the left side of the screen.
Keep in mind that when forwarding multiple messages from multiple parties involved in the conversations iOS 7 won't differentiate the messages. They will be sent as one chunk of text, with no context as to who said what.