Help on IPTC

Hi, We are in the process of developing a Windows application to read and write IPTC information to an image file. We want this file to be Adobe Photoshop compatible. I cannot seem to find any information on developing applications which support IPTC and would appreciate any information you can provide us on the file format of a jpeg image file with IPTC info, e.g The byte Markers for start of IPTC records and Start of Image block etc.. Also, do you know of any tools we could plug in to our application to get this functionality. Thanks and Regards, Padraic Muldoon Imagine Software.