http://www.activebass.com is ****ing awesome! Its got a line builder, and a track builder. Its great for getting the small details worked out on your bass lines. Theres also tons of lessons and info that will help you become a better bass player.
I am not affiliated with the site, besides being a member. So im not just trying to promote a site. It really is a great site. Here's a link to the music I have put up there myself:
http://www.activebass.com/default.asp?src=l&l=20954&p=1