During the whole ISO mission, ISOPHOT carried out more than 17,000 observations. The rich data from these observations (except for polarimetry) can now be easily accessed in the ESA's ISO Archive available through either IPAC or ESAC. (Note the former address usually leads to faster browsing if you reside in U.S.). Anyone who is interested in ISOPHOT data is encouraged to use the ISO archive.
As one can imagine, ISOPHOT is a very complicated instrument, involving many different detectors, filters, apertures, and observing modes (called AOTs or Astronomical Observing Templates ). Consequently, a significant part of the ISOPHOT data have not been scientifically validated. There is still on-going calibration effort to validate all the ISOPHOT data. To check if your particular observations are among those validated modes, please check the official Release Notes on ISOPHOT Data from the Latest Version of Pipeline.
The following sections give some specific information on the ISOPHOT. If you have any question or need any help, please don't hesitate to ask for help at ISO Helpdesk at IPAC.