It depends upon the situation, your audience and the topic of your speech. A simple "Good morning (afternoon, whatever), I'm (state your name) and I'd like to talk about (give the general topic of your speech)" is probably find for a five minute speech. If someone introduces you, and therefore has already announced your name, change the sentence to "Good morning, as (moderator) mentioned, my name is __________ and I'd like to talk to you about....."
Is this speech an assignment for a class? Or are you giving an actual presentation to some group? If the audience has assembled specifically to hear your speech, you should also thank them for coming in your introduction.