Unfortunately, Portland ME doesn't have a Craig's List.  Need sources
to locate housing on a weekly basis, room or otherwise; NOT corporate
housing like Marriott, etc.  Any ideas?  Specifically interested in
the Portland area.  The main newspaper in Portland has virtually
nothing.  Looking for a rental for 1 to 4 weeks, was hoping to find a
source where someone had an extra room would rent it out, etc.  Needs
are minimal.

Dear Pepper, 

First of all, although Craigslist do not have a special section
regarding Portland, their Maine section is full of Portland
apartments. You just have to search by the keyword "Portland":

Craig's List
<http://maine.craigslist.org/cgi-bin/search?areaID=169&subAreaID=0&query=portland&cat=apa&minAsk=min&maxAsk=max&bedrooms=>

Yahoo! Local has many listings, although some of them are, indeed,
corporate apartments:
Yahoo! Local - Portland ME
<http://yp.yahoo.com/yp/Portland_ME/Real_Estate_Apartment_and_Condominium_Complexes/8014813.html>

For more companies, you could also check out SwitchBoard
<http://www.switchboard.com/Apartments/Portland/ME/73-/yellowpages.htm> 

Apartments.com also lists some possibilities: 

Apartments.com
<http://www.apartments.com/search/oasis.dll?p=ypyahoo&Rent_Minimum=0&Rent_Maximum=9999&allsizes=1&am37=0&mode=4096&current_criteria=%26area3%3DY%26subarea2%3DY%26allsizes%3D1%26allbaths%3D1%26state%3Dme%26rgn2%3D125%26prvpg%3D5%26partner%3Dypyahoo%26type_listing%3D1%26srt1%3D0.88%26srt2%3D0.03%26srt3%3D0.05%26Rent_Minimum%3D0%26Rent_Maximum%3D9999&page=Results&area3=Y&subarea2=Y&state=me&rgn2=125&
partner=ypyahoo&prvpg=5&cont.x=59&cont.y=8>

About.com has a very good links guide, both on where to find
apartments for rent, and on relocating to Portland in general:
Portland, ME @ About.com 
<http://portlandme.about.com/cs/realestateapts/> 

I hope this answers your question. It is sometimes difficult to find
an apartments in small cities like that. Another solution that
sometimes works is to go to local universities or colleges, simply
browse the small ads (or to contact them, if you're not there yet) and
enquire about the solutions they offer to short-time visitors:
Fame Maine
<http://www.famemaine.com/html/education/directory.html> 
Please contact me if you need any clarification on this answer before you rate it.