it seems that desktop applications(c#) are unable to use the google apis as they can only be used by web languages like asp or php
Not true, if you call an api over the internet the target can't tell what generated the call (unless of course you tell it)
The biggest descision for any sw nowadays is do you do a desktop app or a web service. That will limit your choice of language as it's difficult to use some on the desktop (PHP, ASP, PERL) but even then not impossible.
However you can develop a web service in almost any language that will run on your server. (perhaps easier in PHP, or ASP but possible in VB any flavor of C ,python etc)
Personally I use VB6 for desktop apps and ASP for web services, however I've developed web services in VB6 in the past. This of course limits me to windows hosting.
If I were starting out I would use PHP instead of ASP (only because it's more portable)
I wish there was a similar choice for desktop portability, that had decent UI capability. I released a trial of something the other day for windows, two of the first four questions, is there a mac version, is there a linux version...