Update 13/04/2012 - You can now order Sky Fibre Unlimited broadband on the Sky website.
Sky Fibre was announced some time ago, and today sees it launch, though as of 9am the same registration page is showing, rather than a full product listing.
Sky Broadband Unlimited Fibre is an up to 40 Mbps downstream, up to 2 Mbps product, and uses an unbundled telephone line, so is only available if you take Sky line rental too. There is no requirement to buy any Sky satellite TV service. The service is a £20 a month, plus telephone line rental of £12.25. This £32.25 also gives you free evening and weekend calls, for another £5 you can have unlimited anytime calls.
While most exchanges where some cabinets can supply FTTC will have a Sky LLU presence, there will be some exchanges (most likely in parts of Cornwall) which Sky has not unbundled and thus the fibre product from Sky will not be available.
Sky Fibre at £32.25 and £37.25 compares favourable to BT Infinity unlimited at £40.60 and £45.50 (line rental included), though for those chasing faster upstream BT Infinity wins at up to 20 Mbps. Also for those close enough to the cabinet (within around 500m of the cabinet) speeds above 40 Mbps are possible as the service offers up to 80 Mbps downstream. The roll-out of VDSL2 profile 17a has taken place across the Openreach network already, so in reality only those already getting the full 40 Mbps download or 10 Mbps upload will see a boost from the 80 Mbps service.
Though the website isn't updated yet, looks like their Customer services have finally been trained in Fibre. Give 08442 411 818 a call, there are reports from Sky's forums of people ordering through there.