We currently using Active PDF software in our farm, which converts documents into pdf and merge them using our K2 back end coding,
however I am looking for something easier, well doesn't matter even if its easy to implement or not but should be free and able to convert any MS Office document (word, excel, powerpoint) into pdf format.
e.g. iTextSharp, but its not free for commercial environment
I might even consider Developing something in C# if its possible.