In reply to Mr Fuller:
Last year I did my 1st sprint triathlon, on not very much, or more like no training. Similar in that was reasonably having done lots of cycling, a bit of running and having never swum that far doing front crawl before. The girl in the lane next to me did breast stroke the whole way and was faster than my front crawl (12mins for 425m!) but I overtook her within 1 min on the bike...
Summary would be don't go hell for leather in the swim as you'll much yourself up for the bike. When you get off the bike all the blood will be in your quads and so it'll be quite hard to balance for a few secs.
Practice oyur changovers as well as you can save valuable time on those by being organised and able to put bike shoes on quickly etc.
There was such a good atmosphere at the one we did definately keen to step up a distance and do the next one... Olympic here we come!