Journal Citation Reports InCites (or JCR) is a Thomson Reuters product and can be accessed from the Web of Science Database. JCR InCites is an authoritative resource for finding journal impact factor data. This database provides impact factors and rankings of many journals across many subject categories in the sciences and social sciences. It offers other journal metric options including Eigenfactor score, article influence score, total cites, total articles, and immediacy index. JCR also provides a five-year impact factor for journals in subjects where citation activity takes more time to increase. In addition JCR Incites provides visualisation trend data.
Also see the slideshow on Journal Metrics.