Our friends from My Speaking Score were cool enough to provide a discount code exclusive to readers of this blog. Register here and at the time of purchase use the code TESTRESOURCES to save 10% on your purchase of SpeechRater credits.
My Speaking score makes use of the same SpeechRater AI used by ETS to score the real TOEFL. You can submit your practice responses and get an accurate score prediction, along with specific scores for metrics like fluency, pronunciation, coherence and grammar. I use it with all my students.
The site provides questions you can answer or you can just upload responses to your own practice questions (like, say, from the TPO sets or Official Guide).