to answer mobike's question: you are 18 and you should have little problem learning how to swim. Learning how to swim fast on the other hand, you are about 14 years behind. swimmers rarely win, because the swim is short compared to the rest of the race. you should be able to gain several minutes back from a bad swim, but it also depends on the distances and your eventual swimming ability. if you were a pro racing an ironman, and you had a two hour swim, while all of your competetors had sub hour swims, well, kiss your chances of winning goodbye. if it is an amatuer sprint, and you have a swim a few minutes slower than another guy in your age group, well, let's just say i am usually in front after the swim, and have a day of getting passed ahead of me.
To answer the ipod question: Bike-absolutely not, and if you are on the road, please do not train with an ipod. You can't hear things, and this poses a major safety hazard. Run-usually not, there is a USAT rule that states no music players at any time. safety seems to be the major reason, but i have heard that it can also be considered pacing help. on the other hand, i pace better without an ipod anyway. It just feels better to listen to your body than to music. If the race is not USAT sanctioned, you might be allowed to use one, but as i think, it is better to go without it.