There are several websites with information about last name origins and meanings, including Ancestry.com, BehindTheName.com, and Surnamedb.com. Some of these websites also help people find immigration records and other details about their ancestors.
Surnamedb.com gives the most detailed information of the three websites mentioned. It has background information about where and when the name is thought to have originated, what it meant at the time, and how the meaning has changed over the years.
Ancestry.com is a meticulously researched website designed for people who want to find out more about their ancestors. It includes historical documents such as immigration records, voting and census lists, family trees, and military records. This website is good for finding out about ancestors and even previously unknown living relatives, but it doesn't give very detailed information about origins of family names. It says which country the name originated in and a brief description of its meaning but gives no further information.
BehindTheName.com gives information about when and where a last name originated and what it means, but the information is not as detailed as that found on Surnamedb.com. Users with less common last names might not find their names listed. However, the website also includes information on given names, which may be of interest to some users.