http://www.ewg.org/cellphoneradiation/Get-a-Safer-Phone

The most dangerous phones - from higher radiation to lower:

HTC Android myTouch ---------- 1.55 W/kg H!H!H!H!H!
Blackberry Curve 8330 --------- 1.54 W/kg H!H!H!H!H!
Apple iPhone 3G ----------------- 1.39 W/kg H!H!H!H!H!
Samsung Omnia (SCH-i910) -- 1.31 W/kg H!H!H!H!H!
Nokia 5800 XpressMusic ------- 1.29 W/kg H!H!H!H!H!
Apple iPhone 3G S -------------- 1.19 W/kg H!H!H!H!H!
Palm Pre --------------------------- 0.92 W/kg H!H!H!H!
Nokia 7510 ------------------------ 0.84 W/kg *I*I*I*I
Nokia 5610 ------------------------ 0.81 W/kg *I*I*I*I
Nokia N900 ------------------------ 0.80 W/kg *I*I*I
Nokia N97 ------------------------- 0.66 W/kg *I*I*I
Samsung Impression (a877) --- 0.35 W/kg *I*I

EDIT:
Added N900 and N97. Thanks Benny1967 (according to sar.nokia.com)