I use Apples Universal Access, and the Text-To-Speech functions found in VoiceOver. VoiceOver is more than just the reminants of MacInSpeak TTS, but is also a screen reader and navigation tool. This just for clarity.
There are several ways to go with this, see below.
1.) Create audio files from from OS TTS directly. Bennifits fast and free. Books2Burn is a good utility that takes text and quickly uses TTS to create audio files. Books2Pod you can hear and read text on your iPod at the same time. Other tools are [http://homepage.mac.com/dougeverly/orator.html]Orator[/URL] which creates a fan TTS audio file from text, and SayBert which does the same. There are others, but thats what I use.
I have my system set to do TTS with what ever I highlight when I press F12. The following are based off being able to use TTS with in OS X. MS word offers a speak function, if you cant or dont use OS X shortcuts.
2.) Use audio routing and combined recording programs.
Get and run one of the following programs. WireTap is a routing and recording program similar to Audio Hijack. You can rip and record from streams, DVDs, speakers, jacks, and the microphone. Both are good programs, and the limited version of WireTap is free. Each of these programs allow you to record from the mic, system, and in some versions from other sources. I like WireTap Pro, which is less expensive, but has fewer options. Both are good, really.
3.) Use an external audio routing program with a recorder. Here are two free options. For free audio routing I would use Cycling 74 Software offers SoundFlower and SoundFlower Bed for free. There are others, like Jax or use Jack Tools-also free routing. There are complaints that they are glitchy, but I havent had problems. I use SoundFlower (see above) though. Once you load any of these programs, you can set audio output to go to a channel and then record from that same channel as a source. A good ultra simple recording app is Audio Recorder.app- It has some other features, like recording on a schedule It also has a clip warning. Another free recording app is Audacity- Free/open source cross platform audio editor For a free product, it really is good. Add the LAME plug-in for MP3 conversion. It is VST and NYQUEST plug-in compatible. There are at least a few hundred plug-ins that it can use-so have at. It was programmed in JAVA and is open source, so the code is not completely optimized. In short, a lot of overkill and a bit slow at times.
4.) For short bits, use another TTS. ATT TTS is some of the best out there. I wish Apple would license these voices and speaking algorithms. It really needs to get out of the dark ages of TTS voices. Really!!! So you could use method #2 or #3 with this engine if you only are speaking short bits. Or if you own QT Pro, you can save the files from the browser. This is only good for short bits, unless you find a vendor that has licensed the ATT TTS for online streaming of text. In that case you could use a stream recorder like iNet Stream. it is not a recorder for you Mic, but it will record streams, and strip off the coding so that it is iTunes compatible. It is worth the 15 bucks, but off course this is only used to run quality control on your own streaming audio.
The down side with methods 2,3 & 4 is that they are in real time, where as method 1 just creates a file quickly.
If you interested in audio apps for OS X then here is a GIANT list of them.