Well I had the problem for a month only in september last year. And it will be a month soon since the problem started in May this year. I am hoping that within a week, the networks and RIM would have solved the situation.
I believe the problems lies within the service books.
1.Go to options (the spanner icon found on your home screen)
2. In OS5 click on "advanced" and scroll down to "service books"
3. Find "blackberry internet browsing service 2" and delete.
4. For OS6+7, once you are in "options" screen type "ser" or "service", this will bring up service books tab and now STEP 3.
5. DO NOT REBOOT or switch off phone. This will replace the service book.
NB: you will need to peroidically to do this when severe sluggishness is noticed. When the carrier re-freshes the network server all service books are pushed over to your phone again. Forcing you to find and delete this service book.
Dear users Please tell me what versions of the Blackberry operating system are you'll using and if it has the slow internet. I keep getting told by my network to update my software. I am using V5 operating system.