Please excuse this newbie question.

I'm having a home built in mid Michigan and the final grade was just done. I
do not want to suffer through the fall and winter with a muddy yard (I've
got a big dog and 3 young children). Is there anything I can plant now that
will hold the soil in place and act as a nutrient in the spring when I plan
on putting in my lawn & garden?

Seems that once I heard of growing alfalfa and plowing it under in the
spring, that this would supply the soil with a good nutrients and be a good
source from which to plant grass.

I'm running out of time and am desperate to get something in that will hold
the soil in place (I've got some slopes that I don't want to erode).

Does any body have a suggestion that might take root yet this year, not look
to ugly through the winter and create a positive base from which to build my
lawn on in the spring? (I know that's asking a lot)

Any help, ideas, urls are welcome!!