Houses and businesses that are for sale on Skye can be placed with many different estate agencies. You will, though, find most of the property that is on the market by looking through these local agents' sites.
If moving to Scotland from elsewhere in the UK, don't forget that the Scottish legal system is not the same. You'll need one solicitor to deal with your sale and another one to deal with your purchase. There is a guide to the Scottish system of property purchase on the IOSEA website.