How do I tokenize a string sentence in NLTK?

I am using nltk, so I want to create my own custom texts just like the default ones on nltk.books. However, I've just got up to the method like

my_text = ['This', 'is', 'my', 'text']

I'd like to discover any way to input my "text" as:

my_text = "This is my text, this is a nice way to input text."

Which method, python's or from nltk allows me to do this. And more important, how can I dismiss punctuation symbols?