FAQ
Is EndNote the only bibliographic formatting software available?
In addition to EndNote, Thomson/Reuter also offers the program Reference Manager. Another application that is on the market now for some years is web-based Refworks. Open source free application Zotero is gaining popularity as well as Mendeley and Papers (for Mac).
See for an extensive comparison the Wikipedia page on the comparison of reference management software. EndNote and Mendeley are supported by WUR Library.