From Mendenyo Yahoo group:
Dear All, I've updated the Worknets Welcome and SendingAirtime pages,
to reflect the latest info from Asif...
Please Note (31 Jan 2008): If using http://www.mamamikes.com/,
AsifDaya says that airtime is delivered instantly, if you pay by
credit/debit card, but delayed for checking if you use Paypal, etc.
Their Kikwe service is also instant http://www.kikwe.com/
Old note (30 Jan 2008): Mamamikes is suffering from delays of 1 or 2
days in delivering airtime. A better option may be their Kikwe
Instant Delivery service, which SashaMrkailo mentioned. I think it
gets airtime to the phone immediately, without human intervention or
checking of the order. I received an email today from Mamamikes,
saying "Delivering Airtime Instantly - We developed a new service
offering instant airtime delivery called KiKwe.com (at the sametime
we are upgrading MamaMikes to send airtime instantly). We will offer
you these services to the best of our ability." - Ricardo