To be able to view your ProsperWorks contacts on your iPhone, there are 3 easy steps:
1. Enable Google Contact 1 way sync in ProsperWorks: Go to Settings > Google Sync > check the "Google contact 1 way sync" box
2. Add your Google Contacts as a contact source on your iPhone: Directions are here
3. Move your "ProsperWorks" labeled Google Contacts to your "My Contacts" folder: ProsperWorks syncs your contacts into a Google Contacts folder titled "ProsperWorks"
To move these contacts, select them all and then add them to the My Contacts group:
This will move your "ProsperWorks" labeled contacts to your iPhone so you can see who is calling you!
You'll just need to remember to move your contacts from time to time so they update on your phone.