Political Parties Websites
Among the resources provided at Project Vote Smart is a list of all current American political parties and their contact information.
OpenSecret.Org, a nonpartisan political watchdog group, tracks the money flowing to American candidates and parties. To facilitate your analysis, donations to specific recipients are sorted by region, industry, and individual name.
This useful site hosts an extensive collection of electoral maps illustrating election results, spending and endorsement patterns, and even types of electoral equipment. There are also historical electoral maps charting elections to the middle of the nineteenth century.