Depends a bit on how you're intending to tackle the peak and which one - the 'trekking peak' tag is a bit of a misnomer, as some of them are technically pretty hard, though I guess you're talking one of the easier ones like Island?
The basic snow and ice techniques you can learn in Scotland or the Alps, but you also need to know about glacier travel and crevasse rescue, which is a lot to chew off in a couple of days. If you do an organised trip though, they should be able to teach you the basics on the mountain. If you're going it alone, or with a local guide, and it's quite easy to do that, then you probably need a bit more experience to be safe.
Jagged Globe -
www.jagged-globe.co.uk
do 3-day Scottish winter courses as well as introductory alpine training weekends.
Glenmore Lodge -
www.glenmorelodge.org.uk
do a mini winter skills weekend course.
Plas y Brenin -
www.pyb.co.uk
does short winter mountaineering and winter skills courses in Scotland.
The last two are both national winter sports centres and very well respected, mentioned Jagged Globe because they run trekking peak expeditions etc, so are well aware of the requirements and again, have a good name.
Combination of a winter skills course and an alpine weekend might be the way to go.