what is a good one, verizon used to have a paid app but its now gone.
Head over to Google and setup a google voice account. Once you've made one, add your phone as a device. Google voice transcribes voicemails and sends them to you via text and/or email format. There's also an app that allows you to see all your voicemails and missed calls. This is what I use to get my voicemails transcribed for me to read while I'm in a meeting or something else.
Note, the transcribing isn't amazing. It works so you get the general idea... but any electronic transcribing service isn't going to be perfect. Just a warning!