I found this interesting. During solar storms, the sun sends out corona mass ejections (CME). These produce deadly levels of radiation. However, they also deflect galactic cosmic radiation. Since we can shield against CMEs and not cosmic rays, it may actually be safer to travel during solar storms. Good times to visit the Moon and Mars may be around 2011 and 2022.
As an interesting aside, the solar storms of the coming solar maximum (2010-2012) may be the largest we've seen since 1958. During that maximum, people spotted the northern lights as far south as Mexico!.