1) Donate to the Red Cross, who has set up temporary housing at the Northeast Minneapolis Armory. More info here:
http://www.redcrosstc.org/detalle_noticias.asp?id=8845&SN=200&OP=210&IDCapitulo=7K58A866M7
2) Volunteer to help cleanup:
Urban Homeworks and the Sanctuary Community Development Corporation are mobilizing volunteers to complete tornado clean up starting at 8AM at 1800 Emerson Ave N Minneapolis MN on Monday, May 23rd.
3) spread the word, stay abreast.
This page is being kept updated: http://www.facebook.com/pages/North-Minneapolis-Post-Tornado-watch/187557157963608
Also, twitter has been great. (aside from the occasional idiotic rumor of course.)
And the Twin Cities Red Cross fbook page: http://www.facebook.com/redcrosstc?sk=wall
It's really that simple.
Thanks and hugs.