EndNote and RefWorks are powerful tools to help you manage your citations and build a bibliography.
EndNote is a client-based citation manager, which means you download the software onto your computer. It can be used offline.
The client-based version of EndNote can be downloaded here.
Additional information and EndNote help can be found here.
Unlike EndNote, RefWorks is completely web-based. This means you can use your account anywhere you have internet access, but it is unavailable offline.
RefWorks can be reached here.