For web developers who want to detect disposable e-mail addresses, I've had good luck with http://www.block-disposable-email.com. It's a good replacement for the (now defunct) undisposable.org/undisposable.net.
If you want to improve the clarity of your writing, I also recommend StyleWriter (http://www.stylewriter-usa.com). It's a bit expensive, but the functionality is unique and helpful.
I use http://www.freepopfax.com for the rare occasion when I still need to send a fax. Always worked fine for me. It includes an ad in the fax which might look unprofessional, but I figure it's unprofessional to still be insisting on faxes in 2010. :)