Skinning jQuery Progress Bar
jQueryUI progress bar is a nice lightweight solution that should adapt to a lot of applications since it has a simple API to it.
If you like the way it looks on jquery website you can plug in variables from whatever process you want it to display progress on and it will do fine.
If you want to reskin it and have it look the same across a project like I did, have a look at this jsFiddle which builds on the example from a previous post: