marco:

Warning to non-geek readers: You probably want to skip this post.

Usage:

parallelize {thread-count} < big_list_of_commands.txt

Demo:

(for i in 1 2 3 4 5 6 7 8 9 10; do echo "echo 'Delay $i'; sleep $i ; \
echo 'Done $i'" ; done) | parallelize 4

Now also at sourceforge