Sally I too have ancestors from Ireland Scotland and England and the best site I have found so far is the world subscription of Ancestry.com. I didn't even know any of my ancestors were from Ireland till I did the Ancestry's DNA test. It helped unlock a branch that had been blocked. Good luck with your search. What surnames are you searching maybe I can help.

The best site for Scotland is the FMP site Scotlands People, where you can see the original documents. If your a member of Ancestry then they have transcript copies of Scotish documents, but you cannot view the originals. For Ireland, then FindMyPast, Ireland site has a large selection of dicuments, but you must remember that most of the Irish records were distroyed in a fire, so there are only parts of census records before 1901 which are slowly coming to light in various towen archives.

As for England Ancestry has the best Internet search for Census records and most of the London & Middlesex parish records. FindmyPast has excelant Census transcripts that include the actual address of the household, but the way the new site works makes it difficult to find records now.
Family Search is the only free site that has a masive collection of Parish records and census records, but they only have transcripts, so you can not see the origina documents unlike their US records.

Other free sites are freebmd.org.uk for Births, Marrages & deaths after 1837 and their sister site freereg.org.uk for parish records before 1837

Hello...I am English with a great deal of Scottish and Irish ancestry...all other suggestions are good. I have found much overlooked resources are University Archives...in Scotland you will find that many of the Universities were founded long before many other institutions, The University of Edinburgh in 1582 University of Glasgow 1451 and so on; all Universities in Great Britain have Archives...just go to any of the older Universities and access the archives. Even younger Universities have Archives...they house many ancient books and history on the Civilization of these nations...many documents you will find digitized....it is worth a look...in fact you can use this approach to researching almost anywhere. I found many records on my Mauritian ancestors at the University of British Columbia Archives. South Africa has a lot of information on Irish Settlers .....just take a look you may well be surprised at what you can find.

One resource that has brought me rich insights into my English and Scottish and Irish family in 1700s and pre 1700s is Googlebooks.com. Type in the family name, or an individual's name (even if they may not have been prominent in some way), their occupation, or the places they lived. At the least, you may find some pictures and descriptions of life in their place of residence at the time they lived there, and fascinating history. I actually found books which mentioned individuals and gave insights into their personalities. One book which had been digitized was a diary by a non famous person. One chapter described my 4x great grandfather, who was a soldier, in detail, as an amateur actor in a company of soldiers, who was witty, sarcastic and annoying. :)

Everyone, thank you so much!!! I am encouraged and delighted to now have some definite places to start researching. I have had an Ancestry membership a couple of times, but at least for the short term I need to explore as many free resources as I can.

I appreciate each of you more than I can say, and am so honored that you took the time to help me in my search!

I've been trying to find anyone at all in FindMyPast, and come up with nothing. Apparently, none of my ancestors from the 1600's are there. Ugh!

I am running two projects, similar to one-name studies: Caln Gillean (MacLean/McClain) and Clan Nicol (MacNicol/Macneacail), as you can see they are both Scottish but descendants are spread out all over the world including many in Ireland and England. I have a long list of resources for all three countries, too long to post in a reply. I will try to post a journal instead within the next few days.