Sn0wbreeze developer has hinted for release of updated sn0wbreeze 2.0 that will jailbreak iOS 4.1 on iPhone 4 and 3GS. Current version, sn0wbreeze 2.0.2, supports iPhone 3GS however ih8sn0w plans to add iPhone 4 jailbreak support in the upcoming version. Here is the image posted by ih8sn0w that reveals his plans:
You can already jailbreak iPhone 4 4.1 with limera1n while greenpois0n jailbreak is also expected to release soon.