Some more good news from iBurst! I for one am very happy re. this offer as it costs me nothing extra and effectively doubles my normal bandwidth. (I also have the 'uncapped' after hours VAS)
I'll be checking my bandwidth after midnight to make sure.

http://www.iburst.co.za/neuvo.aspx?link=company_newsitem&blog=9

2011 iBurst FREE mid-month Top Up offer
Last edited 2011-01-14T16:11:02

Dear Valued Customer, as of the 15th of January we’re pleased to announce an excellent iBurst offer to you our valued customer. With no strings attached, you will receive Free top up bandwith of your base package. This will automatically be allocated on the 15th of every month.

Wireless packages:
1 Gig - Free 1 Gig mid-month top up
2 Gig - Free 2 Gig mid-month top up
5 Gig - Free 5 Gig mid-month top up
8 Gig - Free 8 Gig mid-month top up
15 Gig - Free 15 Gig mid-month top up

In addition you still receive the following benefits:
- Discounted after midnight bandwidth usage
- Free email
- Access to email and voice services even when capped
- Unused data rollover for 3 months
- Low out of bundle data pricing

Offer available to all existing wireless and new wireless subscribers only.
Not offered on Prepaid packages and downward migrated accounts.
Offer available from 15 January 2011.