Hi,

 I am new to DNN. I wanted to see if there is a module  - Free or Commercial that would allow me to search an **external** database. The basic functionality that I am looking for is nothing more than a report based on user input - e.g. address of gas stations in <<City>>. I am also interested in a more sophisticated feature - e.g. gas stations close to <<Zip Code>> or <<address>> ordered by proximity.

I did not see any way to get custom parameters for the report feature.

Thanks

Hhmmm......I agree with Chris' question:  Does the module -have- to query an external DB?  Could you instead use some other means of regularly importing data into your DNN database?  You would have far more options over what you could do with the data plus you'd deliver better performance to your end users as you'd be effectively caching the data on your own DB. 
 
Regarding custom parameters for REPORTS:
you're correct in that REPORTS does not support custom parameters besides DNN tokens.  A similar (and free) third party module that supports querystring parameters is the SQLView module.  I've blogged one example of using that module here.
 
-mamlin