Rising Star Games is on track to release Harvest Moon: Innocent Life (known just as Innocent Life in Japan). While the game shares similarities with the Harvest Moon series, namely the main character being a farmer, Innocent Life is a different game. There is more of a focus on exploring the island and less on building relationships with the community. Even the graphical style is a departure from the Harvest Moon series as you can see from these screenshots. There is no word of Innocent Life coming to North America, but since the PSP is region free importers can snag an English copy of the game on March 30, 2007.
Edit: Pichi informs us that Natsume is indeed releasing Harvest Moon: Innocent Life in North America under the name Innocent Life: A Futuristic Harvest Moon in the second quarter of 2007. They are also bringing over Rune Factory under the name Rune Factory: A Fantasy Harvest Moon for the DS in the second quarter of 2007 too.