This is an interesting question! I combed through this Wikipedia entry and would list these states as having a pro-American orientation based on official foreign policy by governments, not populist opinion. I think that’d be a very different list.
The time taken for my intense research was due to the few minutes I have now waiting for dinner and looking at relatively recent (post WWII) developments.
Israel – Strong cooperation in all diplomatic dimensions and shared adversarial relations with a variety of Middle Eastern states
Republic of China (Taiwan) – Shared adversarial relations with People’s Republic of China (China)
South Korea – Extensive humanitarian aid and military support from the US, shared adversarial relations with North Korea
India – Excellent trade activity, shared adversarial relations with Pakistan
Bulgaria – Significant participation in recent US military campaigns, joint military bases
Kosovo – Supported their move for independence through shared ideologies and continues to support through aid funds.
Poland – As mentioned by seVen, very close ties through continued military support and participation in a variety of modern US campaigns. Has commited to supporting an American interceptor that was to be part of the Star Wars missle defense system (this now looks unlikely under Obama)
Japan – Serves as a strong partner to the US – Asia relations. Close economic, military, and even cultural exchange ties. A shared concern over a more powerful China (PRC) and North Korea’s instability.
I would not agree that Iraq has amenable ties with the US right now. While the interim government does, it’s not in a strong power position and there are significantly stronger political powers in Iraq that vehemently oppose US intervention.
Interesting tip – if you ever want a quick read on US – X country relations virtually every country has a ’country-United States relations’ article. Either plug the country into this URL: en.wikipedia.org/wiki/country-United_States_relations or Google search for “United States country relations wiki”...