How to attribute content

1. You must attribute the work in the manner specified by the copyright holder (but not in any way that suggests that they endorse you or your use of the work).

The Creative Commons FAQ has this to say about attributing CC-licensed works:
If you are using a work licensed under one of our core licences, then the proper way of accrediting your use of a work when you’re making use of an exact copy of the work is:

• to keep intact any copyright notices for the work;
• to credit the author, licensor and/or other parties (such as a wiki or journal) in the manner they specify;
• the title of the work; and
• the URL for the work if applicable.

You also need to provide the URL for the Creative Commons licence selected with each copy of the work that you make available.

If you are making a derivative (i.e. modified) use of a work licensed under one of the core licences, in addition to the above you need to identify that your work is a derivative work. For example: ‘This is a Finnish translation of the [original work] by [author]’ or ‘Screenplay based on [original work] by [author]’.

These instructions are clear in theory, but many people who apply CC licences to their work do not specify how they would like to be attributed. On sites like Flickr or ccMixter, you might not be able to determine the creator’s real name, and sometimes the work doesn’t have a title.

2. In practice, you can handle the attribution requirements as follows:

• ‘Keep intact any copyright notices for the work’: If a work you are using has a notice that says ‘© 2008 Molly Kleinman’, reproduce that notice when you credit the work. If such a notice does not appear, you do not need to worry about it.
• ‘Credit the author, licensor and/or other parties (such as a wiki or journal) in the manner they specify’: If a creator/author has a note attached to her work that says, ‘Please attribute Molly Kleinman as the creator of this work’, then attribute Molly Kleinman. If there is no note, but there is a copyright notice, attribute the copyright holder named in the copyright notice. If there is no note or copyright notice but there is a username, check the creator’s profile to see if it specifies how to attribute the creator’s work. If it does not specify this, attribute the username. If there is no creator name of any kind, but there is a website (like Wikinews), attribute the website by name.
• ‘The title of the work’: If the work has a title, call it by name. If it does not have a title, you can say ‘This work by Molly Kleinman…’ or ‘Untitled, by Molly Kleinman…’, whatever seems appropriate.
• ‘The URL for the work if applicable’: Link back to the original source of the work. This can help creators keep track of places where their work appears by seeing what links are driving traffic to their websites. It also gives users of a work an easy way to track down the original source. If you are reproducing a CClicensed work in a print format, you might prefer not to include a long URL, and there might be situations where leaving out a URL is appropriate. But in general, the link is the most valuable part of the attribution.
• ‘The URL for the Creative Commons licence’: The original work should have a link to the licence under which it was released, and you need to link to this licence. You do not need to include the full text of the licence when you reproduce a CC-licensed work.

3. There is no standard way to format the attribution of a CC-licensed work, and you can adapt the style or phrasing to suit your needs or the standard citation style of your discipline.
4. The licences do not require you to inform a creator that you are using his/her CC-licensed work, but it’s a nice thing to do. Most people are very happy to learn that someone is using and building upon their creations – which is why they use Creative Commons licences.
5. Then using content that has a Share Alike (SA) option, remember that this only applies to derivative works/‘adaptations’, whereby you have to re-publish your version according to the licence conditions of the original work from which you drew your adaptation.
6. However, if you wish to use a CC-licensed work in a manner that is not permitted by the licence, you can ask the copyright holder for permission to use the resource in a manner that you would like. If this permission is granted, then you need to attribute the work in the same way as outlined above. 

Note: This section includes content by: Molly Kleinman (2008). CC How to #1: How to attribute a Creative Commons licensed work.