College Job Hopping?

[DWarrior]

What's the etiquette regarding going to work once I tell them I'll start? I started looking for work last week and took the first position I got, which is basically mailroom work with low pay, and I'm way overqualified for it. Yesterday was my first training day. I already got 2 interviews for other jobs that are better and will probably pay more, but I don't want to leave this job in case the others don't work out or the hours on those jobs are different (one is work from home), so I may even be able to have 3 jobs. This is also only a week in, so odds are I'll get interviews to even better paying jobs in the future.

I realize it costs the companies money because the employees invest some time training me. Is there an etiquette or something to the minimum time I must stay there?