Ancestry/Genealogy

Ancestry has very little Scottish info. The Scottish govt has cut a deal with FindMyPast and Ancestry doesn't have permission to make images of UK census records for Scotland available even, so you're left relying on their abysmal transcriptions for 1841 onward.

FreeBMD covers only England and Wales. But for anybody using it and wanting certificates, always remember to order them directly from the GRO and not from an intermediary, including Ancestry, as you will be ripped off severely.

http://www.gro.gov.uk/gro/content/
http://www.gro.gov.uk/gro/content/certificates/default.asp

But back to Scotland:

http://www.scotlandspeople.gov.uk/

Register free, search free. You have to buy credits to see results. They are cheap. You can view a page of search results for almost nothing. Downloading a copy of an actual record costs a bit more.

It won't help you, but for general info, the site has Scottish censuses 1841 to 1911.

The other databases are:

Statutory Registers 1855-2009
(registration began in 1855; access to recent records is restricted and has to be requested by mail)
Births
Marriages
Deaths

Old Parish Registers pre-1855
(theoretically back to 1538, the earliest records, but coverage before 1855 is spotty -- I did find my grx3 grfather from southern England remarrying there circa 1840, inexplicably, and his wife's death there, but damned if I can find anything else about her)
Births & Baptisms
Banns & Marriages
Deaths & Burials

Catholic Registers 1700s to 1900s
Births & Baptisms
Banns & Marriages
Deaths & Burials
Other Events

familsearch.org does have many of these records -- I see my grx3 grfather's marriage is there now, as records get added. I was able to get the actual image at SP.

So if, for instance, you have the names of a couple who emigrated to the US, you could try parish registers at SP to see whether you could identify their marriage.

If so, you would have struck gold, because there's a good chance it would name both parents of both parties, including mother's birth surnames. And then if you could identify their deaths in Scotland, the death records would give both of their parents' names, and possibly their marriage details as well.

- Edit - or if you know the name of a child the couple had in Scotland who emigrated with them, the child's baptism record might give both parents' names and the parents' marriage info. Or if you just know the name of one person but have a good idea of the person's year of birth, you could try for their baptism record.

In English parish records (registration there began in 1837), by the time you get back to the late 1700s, you often find that only the father's name is given in baptism records, and if the mother is named there is virtually never a surname.

Scottish parish records are very complete in that regard, whereas English marriage registrations, for example, give only fathers' names for the parties.

If you are comfortable PMing me I could take a shot at helping with an SP search, but I don't have any active credits at the moment -- they expire after a certain time -- or I'd volunteer them for you.