Personal development to me means the development/improvement of your own human skills, things that are not specific to a job, workplace or profession. Things that are developed in personal developed are usually things that can be and are used in any walk of live.

An example of a personal development would be listening skills - they are used and are important evening things such as a casual conversation with a friend. However, improving your listening skills can help you learn better and take in knowledge with greater ease. Another example of a personal development would be the improvement of time management to a person. Improved time management can result in a person being more productive with their time and therefor should result in a greater dealing of deadlines etc. A common personal development area is self confidence - many work to improve on this. A greater self confidence can result in being able to communicate better and therefor potentially having a greater job interview success rate etc.

Professional development on the other hand to me means the improvement of skills that are based around/in/for work, the workplace, a career or for a certain professional field. Professional development areas don't tent to cross over in to personal lives or other professions, they can be very specific.

An example of a professional development would be the improvement of skills based around the software of the company that you work for. This is as it is something that specifically improves you at your job and is very specific to the field. A benefit of doing such a thing would result in better performance in your job - potentially leading to promotion. A second example would be to get qualifications or take courses in a certain subject/topic - this would improve you in that field and allow greater job opportunities as some jobs require a certain level of qualification. A third example would be the development of skills managing the troubleshooting/big management within the workplace - this would be improving how you work with bugs and problems specific to your workplace tasks. This would allow you to encounter less problems potentially and deal with any problems with greater ease.