You may want to consider using Craigslist for nationwide job searches because it has some advantages. For one it does not appear in the major job board aggregators like Simply Hired or Indeed - so it may not get flooded with job seekers. Secondly, if you are looking for a telecommute position, a Craigslist posting may be the only place you will see the ad placed- especially with smaller companies or smaller markets.
Craigslist also has the great feature where you can narrow your job search to only telecommute positions. Just check the box and only telecommute position appear. There is also a section at the bottom which show similar results in local areas. This is big, because it saves you time from goign to the smaller craigslist market sites. For example, you can go to the bg Atlanta Craigslist sight and it can give yu recommendations for the smaller Northwest Georgia site without actually goign there.