Will a US Playstation 2 work in Brazil?  Brazil uses pal-m standard. 
I have heard it is like ntsc rather than PAL, but I am not clear. 
What problems would there be with an NTSC playstation 2 for use in
Brazil?  Are the games sold in Brazil PAL or NTSC versions?

PAL-M is also 486 separate horizontal lines of raster arrayed
vertically (525 including the vertical interval), with 60 fields per
second (30 interlaced frames per second), but the color burst signal
(inversion by 1H) is handled differently than NTSC .
PAL-M is not compatible with PAL, but the black & white part of the
signal is compatible with NTSC. Only Brazil & Laos use PAL-M

So your games would come up in B/W  

Brazil is compatible with a PAL playstation according to this website

http://www.absolute-playstation.com/api_faqs/faq10.htm

Another solution could be a NTSC TV. In Brazil the new TVs come with
the option PAL-M and NTSC.
If you get a NTSC TV you would be able to play your games in colour.
But remember that you can not buy any game in Brazil.