PHP Email and Update System

We require a simple request and receive update system using html and php (maybe small amounts of javascript). The system will send out via email requests for an update on legal cases and then keep these updates in a basic management system. The basic function will be: User sends out requests to multiple clients for an update on a legal case. The client receives a link to a data capture form where they can fill in an update on the case. the client fills in a text box with an update and submits it to the system The system then logs this update in a 'file' so the users can then search for a case and find the update. These emails to the clients will be weekly. A site map has already been drawn up and in its basic form is approximately 20 pages- alot of the pages will be of dynamic php content. Although the site map is ready it does not have to be exactly like the site map- I welcome creativity so long the basic function displayed in the map is adhered to. If you would like to have a look at the site maps please message me. My initial thoughts is that the system will use php mailer but further advice on the mailing system is welcome. It should be easy to migrate the code to a new server if required. Please link to previous work if applicable. Contact will mainly be via email- due to circumstances skype is difficult.