Hi Kelly,
Is it possible that at 500MHz you may be better off with a RC filter or to figure out a way to use the VGA as part of the feedback loop for an active RC filter. The reason I ask is that as stated by RFICDUDE the inductor will not be economical and you may want to look for alternatives. I am not sure what your area or current budget is or even the process you are using, but if you are using an expensive less than 90nM process then do something else because the inductor will be expensive. Also I f you want a free program to play around or even simulate a filter go to my site at
http://rfcooltools.com and select the filter design button or you could try a free product AADE filter design, or another free product Elsie which can generate a prototype that you desire. but remember the Q will be small around 2 to 4 at 500MHz and this will be your biggest issue in implementation.
http://rfcooltools.com