Join contiguous or contained polygons

[Jerl Simpson]

Hello,

I am sure this question has been asked, but searches I have done don't
reveal what I'm after.  So I turn to you guys.

I am wanting to join contiguous polygons into one shape.  For
instance, I have place where there is a water polygon, and with in
that is another, smaller water polygon.  So I end up with 2 rings in
my map (I need to outline the polygon).  Or I have two contiguous
water shapes, with a line down the middle, where there really doesn't
need to be one.

Does anyone have any ideas if a program does this already?  Or an
approach I might take if I need to write my own?

Thank you,

Jerl