So there are only 2 types of network cards in the world? "ethernet" cards and "dialup" cards?

I wouldn't call a dialup card a network card per se. A dialup card is know as a modem and is used to connect to an Internet Service Provider (or some other remote computer system) via ordinary phone lines. Modems are generally limited to speeds of 56 kb/sec. Ethernet cards, on the other hand, can communicate at speeds up to 1,000,000 kb/sec (or 1 gb/sec). Ethernet cards are used to connect to local area networks (LANs) and are also often used to connect to cable modems or DSL modems that provide high speed Internet access. As another writer mentioned, another option is a wireless network connection using a WiFi (Wireless Fidelity) card to connect to a network wireless. You can set up a wireless network in your home, and many businesses like McDonalds and Starbucks also offer wireless Internet access using WiFi.