I do 95 or so a min, speech recognition can't keep up and has an even worse error rate than me =P 30-40 is perfectly serviceable if you ask me, I wouldn't call it slow at all. I'd consider anything under about 20 slow. My Dad was a PC tech for many years, and he never graduated above the 2 finger 10WPM range, but he has no troubles =)
I'm with BrownOut though, there is no magic device which can help you type faster or is more useful than a decent solid keyboard, anyone that has a gadget and says otherwise is just trying to sell you something. Although I have heard of BAT keyboards, which are single handed keyboard that only have seven keys, chords are used to create any letter or symbol. There is also something called a Dvorak keyboard which professional typists use, it's similar to a QWERTY keyboard only someone with understanding of the English language actually designed it =) a QWERTY keyboard is HEAVILY left hand oriented for common words where a Dvorak keyboard is optimally letter weighted so that only a very short distance needs to be traveled for the majority of letters used in common language.
I personally wish I'd learned on a Dvorak keyboard I'd be in the 150 or so range and not have such bad wrist problems. I thank my current speed to taking touch typing in grade school. It's boring monotonous and takes a very long time but it's the only way to learn to type properly.