This sim will have the following free for 90 days when topped up (I am unaware if the tenner for transferring counts as a top up - although it does mention it as a top up - but you know what mobile companies are like).
Free skype calls (only if your phone can run skype obviously).
Free 150meg of data
Free MSmessenger (if your phone can run this)
Normally there is also 300 (in shop) or 600 (online) free texts with a tenner top up too.
The number of inclusive texts increases with the size of the top up - the lowest top up that would be needed every three months to get the free data and skype and is a fiver (so £1.67 a month). However, a fiver only gets you 25 free texts.
Additionally - the £70 s2 Skypephone has been dropped in price to £39.99 (for a while they say), so with a tenner free credit its only £29.99 AND there is £11 quidco on this too (but actually tracks at £11.78) making the phone potentially only cost £18.21
The only downsides are calls cost 20p per min, and the phone appears to have COD written across the front.