For train-at-your-own pace, tlcc.com is terrific. When you register, you can download a free partial course to learn a little and see how well you like their offerings.
For classroom training, use the IBM training site to find a certified trainer in your area. IBM Training main page.
This is a link to a free ibm.com virtual ND8 offering.
Free tutorial: Building composite applications for IBM Lotus Notes V8.
You may also wish to visit this Lotus Notes Domino application development best practices guide from SearchDomino.com. The tutorial gives some best practices and pitfalls encountered when developing applications in a Lotus Notes Domino environment.