There are a few legalities involved.....wait....I'll go find a link.
http://www.gro-scotland.gov.uk/regsc...d_in_scotland/
http://www.weddingguide.co.uk/articl...chscotland.asp (ceremony procedures)
As far as to 'where' to get married....it will be hard to choose. There are so many cool romantic places in Scotland.