Job interview advice

I had a job interview last week and they gave me the impression that they were going to offer me the job formally once the person that is in HR gets back from holiday, they said I would get an email next week… the job sounds great and I probably will accept it.

Aside from this I have 2 interviews lined up for two other jobs this week and next week. Both have their merits and I would be tempted to take them once I get a feel of what the jobs are like etc…

My question is, I don’t want to burn bridges with people from potential employers in the future. If I was offered a job but wanted to see how my other interviews go first, what can I say to the perspective employer before giving them a definitive answer? I don’t want to mess anyone about.