Well to start with, PocketPC Windows Mobile Professional and Smartphone Windows Mobile Standard have a lot in common and most of the applications designed for PocketPC will run on Smartphones as well. There might be navigability issues because of the inherent assumption of a TOUCH vs NON-TOUCH device. Some of the PPC apps will fail to install on SMARTPHONES. Below is the workaround which works and i have tested it several times.
If you have a PocketPC lying somewhere which you don't use at all, this is time to bring it back to life. Install the PPC app on it, connect to your computer and copy the installed directory over. Now connect your SmartPhone to your computer and copy the "copied app folder" to your smartphone. Try executing the EXE on smartphone now and it will work except for the layout etc..
Try the SPHelper application which will let you simulate a CROSSHAIR (meant for touchscreen apps)
SPHELPER Application Link
If you are not lucky to get hold of a PPC try the following approach. Open the CAB file using Winzip or any zip extraction utility. Extract all the files in the CAB to a folder. The Files will have funky last characters but don't worry. 99% of the CAB files will have a "_setup.xml". This file will tell you the exact name of the installed file and the corresponding funky extension file in the CAB. Use the XML to rename all the extracted files on your computer and copy them over to the SmartPhone.
Sometimes the XML is not present. In that case extract the contents of the Smartphone Version of CAB to a seperate Folder and see if it has the XML file. If not Just extract all the files and try to compare the filenames in the folder containing the PPC files. Most of the times, it will give you a rogh idea as to what file is the EXE file and what are the DLLs. GOOGLE the missing files and you will find some hits for sure...
I have done this with several apps and it works.. :-)