In the past Weber's materials only available most in lecture notes and they were only available via he attended that lecture. Like Josh said, he is very tight on who got his materials and therefore very few materials will be available beside someone who will let go of their procession of Weber's lecture notes that could be found on like eBay.
A few years ago he release a monthly subscription program called 'Real Secret' that subscribers received one effect per month with props and instruction, subscribers occasionally received download content to assist learn as well. After the end of Real Secret was Psience, a similar subscription that involve six effect to be released, five of them already released and sent to subscribers via email.
Weber's current major release is The Works, a bi-monthly subscription but all props were sent out in a black box WITHOUT instruction at first and subscribers received instruction bi-monthly and only that time they know which props goes with which release. It started July last year and some delay in-between but now get back to its release schedule.
Also, Weber occasionally release lecture notes during his lecture via Blackpool he attended, plus release a few props including Weber Wallet, TEN - his works on Ten Card Poker Deal, Complete Crazy - His work on a magic prop that was in magic set but several more phases to blow audience mind. SEER, a peek wallet type business card holder which can be examined by audience before effect, yet the secret is hidden in plain sight. Best of all it does not use electronic / battery / light of any kind. Just to name a few something Michael Weber released since 2012, unfortunately I am working now so I cannot list out other lecture notes he released during the time mentioned.
I was honored to met him during Magic Con in 2011 as David Williamson introduced me to him, and after that he and Tim Trono allow my subscription to their hard-to-find mental magic / mentalism materials over the years.
If you want to study organic, casual mentalism / mental magic material from close up to parlor situation, Weber's materials are some of the best in the world you can ever ask for in this generation. I personally also hold his materials very tight and not want to see them fall to wrong hands as well.
Hope this helps.