301 is a permanent redirect, that tells the browser that the page has been moved permanently to a new location.
I have used microsites with varying levels of success. Long before I started at my current company, management bought almost a hundred domain names with various keywords for future use, and to prevent competitors from registering the similar domains. After getting our primary web site redesigned and climbing in the rankings, I started working on some of the other domains we own. The main intent of these sites was for me to experiment with different layouts and different database structures, while also giving users a quick way to find out about specific products without going to the more general main site. Originally I planned to delete the sites, until I realized that the sites were generating traffic, and getting good rankings.
Generally speaking, I agree with everyone who has said that the best strategy is to focus on the main site. If you want to localize, I would generally make the localized content part of your main site. That way you can spread the link juice the localized pages receive to the rest of your site more effectively, and it should make management easier. However...
The use of satellite sites really is a common strategy. For instance, Microsoft has a main web site that covers all of their products. They then have a family of satellite sites that each focus on a specific product or group of products. (windows.com, windowsupdate.com, xbox.com, microsoftoffice.com, etc.) But notice that every single one of these sites is independent and self-sustaining.
I think that is a key point. Each site has to be distinct and valuable to the user on its own. If the microsite is just going to say "mycompany.com has information and portfolios about artists in <area>. Visit the site and see what we have for you" don't bother. If the site can stand on it's own, attracting and keeping its visitors for almost everything (with a possible exception for ordering which may still be done through the main site) then a microsite may be worthwhile.