Can I use DLLs developed in C or C++ from Delphi?

Delphi is capable of making calls to and receiving callbacks from any standard Windows DLL. In addition, it is said to be possible (though rather tricky) to get Delphi to access classes within C++ DLLs. Borland's WWW server has instructions on how to do this. I wasn't able to get it to work, but I think that's because I have weird DLLs.