Most of the DVD sets of LOTSW here are PG rated. (From memory a couple of the earlier ones were M rated.)
Over here PG (Parental guidance) is pretty much the norm for harmless stuff. ("Parental guidance is recommended for younger viewers", is the usual voice over warning)
The next one "down" is G, which is basically kindergarten stuff, so PG is the catch all rating and is treated basically the same as "G".
"M" (mature) starts to get the more mature stuff, whereas "MA" (Mature adult) says it isn't suitable for under 15's.
"R" is restricted to 18 and over and is not generally broadcast on "normal" TV and is relatively rare even on cable TV. This is usually the most realistically "scary", "bloody", "violent" end of the market and includes soft porn. It is not the kiss of death to a movie to be "R" rated here and some big blockbusters have received the rating without problem.
"X" rated is technically illegal here and generally relates to hard core porn.