Saberu as Mat said if you do the TEFL you will be as qualified or more qualified than the many folks who grind out the summer camps and the weekend/late night language school jobs. Most of these places are so desperate I am sure they would take you on even if your stay will be breif. As far as the morals of it go, these places for the most part are just an added practice opportunity for the kids above and beyond their normal learning so even if you are only so-so the kids still should get a bit of speaking practice out of it. Do try do the TEFL though because it won't make you a superstar but it will get you started on the right foot.
Not sure if you ar frankaphone/bilingual or not coming from Montreal but if so please avoid teaching them "dis, dat an dee udder ting"! They already know how to murder pronunciation.