The answer is: it depends.
* In most cases, "et" is silent. This is especially true when it is followed by a vowel or a silent "h." For example: "et elle" (and her), "et homme" (and man)
* However, "et" is pronounced when it is followed by a consonant (except for "h"). This pronunciation sounds like "ay." For example: "et moi" (and me), "et toi" (and you), "et le chien" (and the dog)
Let me know if you have any more questions about French pronunciation!