Recently ran into an interesting issue where a client had a purchased Adobe Type 1 font the had been using on their Mac OSX systems and need to use the font on their newer Windows systems. Being that the fonts were Adobe Type 1 fonts and only had the .AFM files this was an issue with using the font on a Windows system, so it had to be converted.
Download and install Fondu to your Mac, the download is a zipped pkg file and just needs to be extracted and installed. Once installed Fondu will be located in /usr/local/bin. Copy your AFM file to a folder or a folder of your choice. Open a terminal on your Mac, it can be found under Utilities folder in your applications on OSX 10.4 and 10.5, which is all I have at my disposal.
Navigate in terminal to the folder where the the afm file reside and type
ibook-g4$ /usr/local/bin/fondu -afm
And Fondu is off to the races. It will extract what it can find in the files and create bdf, pfb and other afm files it finds. If Fondu asks to overwrite it is fine to allow it to do so. Once complete copy the files to your Windows system using a usb drive or other methods at your disposal.
Now install AfmToPfm to your Windows system and open the application. Click on the Add from folder button or Add Files button and navigate to your folder where the extracted files reside and add them. Click on Create PFM Files and like magic you now have PFM files that can be installed into Windows Fonts.
To install the fonts just right click on the PFM files and click install and they will be added to c:\windows\Fonts directory and available to your applications.