This whole web 2.0 phenomena sure brings out some cool services -- with all the beta's you can sign up for these days I've become pretty selective which ones I subscribe to, just to make sure I do get a couple of hours of work done.
Something I recently signed up for is jaxtr, a really cool service that I believe will take off "skype-style" once it is publicly released. What it allows you to do is a couple of things. You can put up a badge on your site that allows people to call you on one of your phone numbers without actual having to publish that number.
When someone clicks your badge they get a local number that they can call (currently supports 29 countries) and it then redirects to your phone. The services gives you 100 minutes of free talk time a month, after that runs out it jumps to voicemail mode which has no limitations. You can also set it up to go directly to voicemail rather than call you which I find an even cooler feature, particularly for something like podcasts.
What happens when you get a voicemail message is you get sent an email with a link to an MP3 you can listen to or download. In your account you also get an overview of all voicemail messages and can set it up filters to block certain numbers.
If you think about it, this service basically gives you the equivalent of local skype-in numbers to 29 countries, 100 minutes of free talk time and a free unlimited voicemail service. Not entirely sure about the business model around this but bring it on... I'm not complaining!
I might just have to write a WordPress plugin to get jaxtr to enable audio comments on a blog post. Shouldn't be too difficult to hack together.
Feel free to leave me a voicemail: http://www.jaxtr.com/peterelst
P.S. If someone has an invite to Joost, thats something else I wouldn't mind giving a whirl ;)