Hi there,
You must be aware that there are tow types of form content types:
1. application/x-www-form-urlencoded
2. multipart/form-data
A normal form, when not defined with any enctype (<form>) is "application/x-www-form-urlencoded"
This would serve most of your day-to-day web needs.
But if you want to send:
1. Large amount of Form Data
2. Non-Ascii Data
3. Binary Data (Files)
You "Should" use the enctype as "multipart/form-data"
Recomended further reading :
http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4
Cheers
Aneesh