The swim: How many times a week are you swimming? If you're doing at least 2 then try to mix it up. Do the full distance one time and intervals the other. I think it's good to get a feel for the full distance and to know you can do it.

The bike: Don't limit yourself to just one chainring. You want to try to stay in whatever gear will allow you to ride at your most comfortable RPM. This is different for everyone. I feel best between 80-85. Others like to ride over 90. You change the gears to allow you to do this. The idea is to be most efficient and fastest without exhausting yourself. What's best for you? You just have to ride and play with it and see. (This may be too basic, but a way to think about gearing is that the closer the chain is to the bike frame, the easier it is to peddle and vice versa. So, going up a hill you'll be using easier gears, ie closer to the frame: small gear on the front and big on the back.)

The run: A lot of people will walk part of the run. This is true for all lengths of races, not just sprints. Do what you can. Nobody will think worse of you.

Www.beginnertriathlete.com has a bunch of free training plans for all lengths of races. They also have a good forum.

Clothing: Definitely get some tri shorts. They're designed to be worn for the whole race. Aerotech and Avero (sp?) both make less expensive tri clothing if that's a concern. I've used the Aerotech bike shorts. The quality is very good for the price. To be honest, though, their tri shorts didn't fit me well.

Get a cheap race number belt. You can find them for $5 or less. You just clip it on in T2 so you don't have to pin anything on your shirt.

I use a tri shirt. I don't like trying to wrestle myself into a shirt when I'm wet from the swim. I'm not that coordinated. I'd end up in a cursing wad.

What you're doing so far definitely sounds like you'll be able to do the distance.

I hope this helps answer some of your questions.