Recently I have noticed a small wiggle on the bottom left side of my monitor, every once in a while it wiggles in other areas of the screen but always at the bottom.

It is not all that noticeable, but I am curious as to what might be causing this.

Thanks in advance.

Is there any magnetic devices nearby like speakers etc?

It could be failing also, you could try reducing the resolution of the screen, the colour depth or the refresh rate.

I do have speakers nearby, but they have always been there. Maybe I never noticed the wiggle before.

How about my DSL router, will this cause the problem?

No, the DSL router shouldn't affect it. If the speakers are the standard PC type speakers they shouldn't affect it either, they are usually shielded to protect from this type of thing.

How old is the monitor, and what type (CRT (deep) or LCD (thin))?