If I wanted to migrate a Parallels Virtual Machine to a VMware Virtual Machine using a VMware product to do it, this is what I do...
In Parallels I would uninstall Parallels Tools, install VMware vCenter Converter (in the Virtual Machine) and then create a Virtual Machine from within Windows XP running under Parallels. After creating the Virtual Machine I'd run it in VMware Fusion and install VMware Tools.
Note that by default a normal VMware Fusion created Virtual Machine is in a Package and with VMware vCenter Converter the files that comprise the Virtual Machine will just be in a Folder. To turn the Folder into a Package just add the .vmwarevm extension to the Folder and hide the extension from Get Info on the Package. (Ctrl-click the object and select Get Info)
