You can't convert a binary executable file into an XML file. Of all the things XML may be, a programming/compilable language it is not. Perhaps you could get a script interprettor that worked with XML, but a translator from an EXE would be another matter entirely.
You might be able to convert a database into XML though. I imagine there are tools to do that, and it could even be done manually. I wouldn't advise it personally, because a straight 'translated' XML version of a small database (just tables without relationships) would be much larger than the original database, and cross-hierachy relationships (i.e. relationships beyond the obvious structure of a document) aren't easy to express using XML.
i want to know whether any exe files not 'db' specific it can be dlls also...
can it be transfered via web services...for which the content or syntax of the file shud be in soap xml format?
are there any special converters present?
Well. CDATA, and I suppose PCDATA also (I didn't even know that existed) are blocks within an XML file that are declared as 'deviant' from the natural XML format.. So If you put your dlls or whatever into an XML file, that wouldn't be converting them into XML, it would be wrapping XML tags around them and saving them as XML.
What you want to do avani, doesn't make a whole lot of sense right now. Why do you want to send DLLs in XML messages? There is probably a more normal solution to what your trying to do, i.e. loading a local DLL based on instructions in XML messages, or initializing the download of a DLL based on instructions in an XML message.
Although I suppose you could theoritically 'paste' program code inside XML and send it around, you cannot convert the syntax of a compiled DLL/EXE (or most compilable source code) into the syntax of an XML file. There's too many reasons why not.