saying 'excuse me'...?

[whaaaatt]

Many times I have heard that sumimasen （すみません）is translated to mean "excuse me". However I was looking at a book called Japanese For All Occasions and it said that Shitsurei shimasu./O-jama shimasu. （しつれいします。/　おーじゃまします。） can also mean "excuse me".

What is the difference between these phrases and when is it appropriate to use them?

thank you for the help!
　どうもありがと！

[micahcowan]

In many cases, all three can be interchangeable.

すみません is an all-purpose "excuse me" or "I'm sorry". It's useful for if you want to apologize for something, if you bump someone's elbow accidentally, if you want to get someone's attention, etc.

失礼します and お邪魔します literally mean "[I'm] being rude" and "[I'm] being a nuisance/bother", respectively. Both, like すみません, are I think often used to get someone's attention (especially if they're a stranger), though I personally haven't heard お邪魔します for that much (but my experience in actually speaking Japanese is limited). お邪魔します is also very commonly used to mean that you're going to visit someone (thereby being a bother to them), and 失礼します is used to mean that you're going to leave now (thereby being rude). They all mean roughly the same idea, and it's much better just to familiarize yourself with the nuances in how they tend to be used (by listening to lots of Japanese conversation, of course), than to get too hung up on the minor differences between their literal meanings.