The amount of data that you can send to the server using WML forms and Nokia WAP enabled phones such as Nokia 3330 and Nokia 7110 is limited. The URL and querystring lengths are also affected since they affect the size of the HTTP header. To fix this problem you have to change the CONNECTION TYPE property to CONTINOUS in the settings menu of the mobile.
The maximum size of a WML page varies between different handsets. When coding WML pages Microsoft recommend that they are less than 1200 characters to be compatible with the majority of cellphones.
Graduated from my CCNA evening course tonight. All that remains is for me to take the CCNA exam. I'll be posting my revision notes here shortly including links to some useful resources.