<p>I wish to know all the pros and cons about using these two methods. In particular the implications on web security.</p>

<p>Thanks.</p>

To choose between them I use this simple rule:
GET for reads. (reading data and displaying it)
POST for anything that writes (i.e updating a database table, deleting an entry, etc.)
The other consideration is that GET is subjected to the maximum URI length and of course can't handle file uploads.
This page has a good summary
.