Xbox 360 FAQ
How to Window Mod an Xbox 360 without a Dremel tool
Jig Saws
Jig saws can be used for case modding. However, you will want to read on before you decide to use one. Jig saws are much more commonly used for computer case modding as those cases are typically not plastic like the Xbox 360 case is. Jig saws are great for cutting metal but much less so for plastic. They are harder to control when cutting plastic and have a tendency to get hotter while cutting than the Dremel tool does. That causes the case to melt more so than it does cut. Tinker Mods would never reccomend using a jig saw to window mod an Xbox 360 console without a Dremel tool
Other options
Cutting the case is only one small part of case modding. If you can't justify buying the Dremel tool and you also do not want to use a jig saw for risk of something going wrong, you do have one other option. You can just as easily buy a pre-made kit. Tinker Mods offers kits just like these, they include LED kits of your choice and have a window cut into the case already.