These wills have been available in a digital format for some time at the National Records of Scotland's Historic Search Room in Edinburgh, and are catalogued on the site's online catalogue at www.nas.gov.uk/onlinecatalogue.
One thing missing from the coverage, however, was an indication of when they would appear online. I have since contacted the NRS to ask them just that, and they have replied that it is the intention to make them available at some stage in May of this year, though an exact date has as yet to be confirmed.
At present it is possible to trace English and Welsh soldiers' wills from the First World War via a new payment based service at https://probatesearch.service.gov.uk/, whilst Irish soldiers' wills from 1914-1917 are freely available at http://soldierswills.nationalarchives.ie/search/sw/home.jsp, with the coverage to extend soon to include wills from 1918-1922.
(With thanks to @NatRecordsScot)
My latest genealogy books are Tracing Your Family History on the Internet (2nd ed), Discover Scottish Civil Registration Records, and Tracing Your Irish Family History on the Internet. My next Pharos course is Scottish Research Online, which commences Feb 27th 2014, 5 weeks, price £45.99.