Which program do you recommend for Mac users?

There is not a great choice for Mac users but one of the best web audio programs on the market in Sonic Memo which work on Macs and PCs.
The other option you have is to use a subscription service like AudioGenerator. With this there is no program to download, all you need to do is paste some html code into your web page, the audio files are stored on the AudioGenerator server.
If you are interested in trying out Sonic Memo but don't want to spent $97, Jay Jennings the creator of Sonic Memo is offering a lite version for a limited time only. To get your free copy of Sonic Memo Lite click here.