Being an entrepreneur requires wearing a lot of hats. Luckily, all the skills involved are things that I'm highly interested in learning. At this point, I've got a "$@#% I Need To Learn" list on my whiteboard (yes, I'm a bit obsessive about whiteboards) and figured I'd share it. I've previously referenced my next few months as an attempt to get an "MBA with a CS Minor""¦ so I've made the beginnings of a curriculum.
Disclaimer: this is absolutely a work in progress

Three major skill areas dominate in the creation of a startup:

1. Product Design
2. Product Development
3. Business Development

I may not be categorizing everything exactly according to traditional lines and a lot of it overlaps but I don't think anyone's going to get hurt for the difference. Obviously, these are focused more on the skills necessary to start a web-based tech company. The way I see it, to be a successful entrepreneur you should be able to establish a competitive business framework, build a high quality product and give that product life with strong design.

1. Product Design
Before you can build a product, you have to know what you want it to feel like for the user. It's a given that you need to have a good underlying product but the great companies separate themselves by engaging the user's emotions with those products. The product design skillset encompasses everything from conceptualizing the user experience and designing the look and feel of the product to actually executing on the front-end development.
A) (x)HTML
B) Cascading Style Sheets (CSS)
C) Wireframing and prototyping
D) User Experience 101
E) Adobe Dreamweaver for website design
F) Adobe Illustrator for logo, branding and web graphics
G) Adobe Photoshop for advanced photograph editing

2. Product Development
In a tech company, this mostly means coding and back end development. I've chosen the Rails route over Django or similar frameworks after a lot of exploration and conversation with practitioners. Rails just seems most conducive to rapid prototyping and iteration on the web while still being a transferable skillset.
A) Javascript
B) Ruby on Rails
C) PHP
D) SQL and database management
E) Hardware architecture and cloud systems
F) Search Engine Optimization (SEO)

3. Business Development
This is an incredibly broad category but luckily there are resources available commensurate with its size. By necessity, it covers every step from ideation through execution and growth.
A) De-risking the idea and customer validation
B) Market analysis and targeting
C) Branding
D) Advertising and SEO
E) Competitive Analysis
F) Leveraging the Social Web (Web 2.0)
G) Accounting for startups
H) Finance and capitalization for startups
I) Contracts and lawyering 101
J) Pitching and Selling
K) Recruiting, hiring and firing employees
L) Management

Miscellaneous skills I want to learn:
These are unrelated to startups but I want to learn them because I am, perhaps surprisingly, not just a worker drone with no life.
A) Motorcycle maintenance and repair
B) Adobe Photoshop for artistic photographers
C) Studio lighting 201
D) West Coast Swing and Hustle
E) Surfing 101
F) Bicycling theory
G) Wine 101

If you've got ideas for corrections, additions or refinements, let me know. Suggestions for which resources are best to tackle a given issue are also certainly helpful. At some point down the road, I'll probably add links to the various sources I'm utilizing.