You will most likely end up getting into Windows API calls. If you have used
this before from COM, make a wrapper. Sure, you end up with two wrappers (one
for Delphi and one for your COM component), but it can work.

The other direction is to look at how other non-COM components are called
(PInvoke?). A quick google search should have at least one API type example.

If it is a COM dll, you can still access it by using COM Interop. You can
add references to COM dlls in a VS project. Also take a look at tlbimp.exe
tool.

-Atul
http://www.ssware.com/
Shell MegaPack - Windows Explorer Shell Controls for ActiveX and .Net

It looks like you are saying that you have a DLL that is NOT a COM dll,
written in Delphi, and that you wish to call it from your vb.net app.

You can do this with PInvoke.  If your app had been written in C++, I'd say
to use a managed C++ wrapper.

Start here:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcn7/html/vaco
nCallingWindowsAPIs.asp