My Nokia N95 mobile phone has this cool feature that allows you to subscribe to podcasts. Given that it has wifi support, I use it to download and listen to podcasts without using a computer (in contrast to the iTunes-iPod model).
The podcast client is not great, but it will allow you to use any OPML URL as a podcast directory, making it much easier to subscribe to new podcasts without having to enter long URLs using the phone keyboard.
So, I needed an "OPML manager", a web application that will allow me to ad and remove podcast feeds and then export this list as OPML. Once I subscribed to this OPML from my mobile, adding new podcasts would just be a mater of adding new feeds to the (hopefully) much easier to use "OPML manager" via its web interface.
It turns out that wordpress blogrolls can be used as a simple OPML manager [*] which is cool because I can use a single app to advertise the podcasts I listen too on my web and use the same list on my phone!
In order to use this feature, you have to add the feed URL of each podcast, when you add them to your blogroll. I have made a single category called "Podcasts", with ID 45 (sorry, the examples are from my greek blog). The list can be seen here: scroll down and you will see that I have two link categories called "Blogroll" and "Podcasts".
Now the OPML for category #45 (in this example) can be found at http://vrypan.net/weblog/wp-links-opml.php?link_cat=45!
(If you are using a Nokia N95, go to Applications->Podcasting->Directories->Options->New and add a new Directory using the above URL)
Dynamicly generated OPML URLs (also called "Reading Lists") can also be used by other apps. It's such a shame Bloglines and Google Reader don't support them (yet?).
-- [*] IMPORTANT! The current version of wordpress (2.3.1) has a bug. In order to get a single category in the OPML file you will have to edit wp-links-opml.php and replace the line
$cats = array (get_category($link_cat));
$cats = get_categories("type=link&hierarchical=0&include=$link_cat");