I've been using Nuance's Dragon Dictation on my iPhone now a few weeks. One of my favorite uses for it is dictating task item into OmniFocus. Dropping new items in the inbox is simple.
Dictate the task into Dragon
Copy the task to clipboard
Open and paste the task into OmniFocus.
The Task Is In
Note that OmniFocus allows you paste items in the inbox even while the database is still updating. This has largely replaced my prior use of the Note2Self app where I would dictate new tasks and then process them after receiving the audio files. I know there are also other options, like ReQall but I prefer the above method.
Also note Nuance has updated the Dictate app allowing you to opt in (or opt out) of sharing your contact names. I know a lot of people felt this was a security risk. I don't think it is that big a deal and uploaded mine.