Jaduka is a web services company aimed at allowing Mashup developers to trigger phone calls from web applications. Essentially, if you want to deploy a button on a web site, so that customers can click and call you or your business, Jaduka has a great offering. I put mine together in about five minutes; you can too. I picked the button I liked the best from their copious gallery, and off it goes. It's working, and I've pointed it at my Grand Central account, if you want to try it. I picked the button below, as I bet Jon Arnold will call me and I don't want to have him dive for his headset again :
Jaduka also provides an API, which has two basic parts. The first manages calls, either calls to the account holder's phone number, or calls between two arbitrary numbers. The second part of the API manages voice mails, so that you can manage them as wave files. As an example of the call management solution, you easily bridge calls between two numbers whenever it makes sense. Let's say you have a scheduled call with a partner. You could make an application that calls you when the appointment starts, then calls your partner. You can also make that functionality point to different places, so that you can implement a find-me, follow-me system, or a skills based routing engine. As an example of the voice mail management solution, you could take your Jaduka account and aggregate reports from remote salesmen by having them call into your number, then taking those voice mails as WAV files and attaching them to your CRM system.
Finally, let me say that whoever is doing product management at Jaduka is doing a great job, because the Jaduka API is small, easy to learn, and provides real value. I didn't have to spend more than fifteen minutes to read the documentation before I felt like I grokked it. Definitely part of my toolbox going forward.