Any and all males who carry the RILEY surname (and spelling variants) are welcome to join this project. As this is a surname project, and only males have a Y-chromosome, only males can be tested for this purpose. If you are female, you can have a male relative submit a sample on behalf of your line, as long as he still carries the RILEY surname.
If you are interested in another type of DNA test offered by FTDNA, just let the project administrator know when you 'request' to join.
If you have interest in the project, but don't wish to actively participate, donations are most welcome. If you wish to make a monetary donation, please go here, the directions are easy to follow but if you have any questions please contact the project administrators.