With only two USB ports, how can I use the standard input devices together with the wifi dongle? The only thing I could think of is to set some accessibility option and use the keyboards arrows for navigating the pointer, but even for that I couldn't get any info online.
You can use USB hub device. This is special device designed for exactly your problem - to multiply the number of USB ports available.
The best option for RaspberryPi would be to use
powered hub (also called
active hub). It differs from the normal USB hub in that it has its own power adapter. This allows you to connect power hungry USB devices (like USB hard drives or some USB wifi cards, etc) to RaspberryPi without any problems. Most devices should be working OK but if in doubt, you can find a list of tested
powered hubs (both working and problematic) on the wiki.
They shouldn't be too expensive and you should be able to find them in most stores with computer parts.
If you don't want to buy a HUB, you can probably buy some wireless keyboard+mouse kit. They usually come with one USB connector for both devices.
Or you could buy a keyboard with a touchpad (like in laptops),
Logitech K700 for example, but these are more expensive.
If you have an old PS2 Keyboard and mouse, you can use a dual PS2 to USB adapter to allow them to share one USB port. Here is an example of one of these adapters from MonoPrice:
All credit and rights for this image belong to MonoPrice. You can buy these adapters in other places, if you want, as well.
Use a powered USB hub.
This is recommended by the Raspberry Pi foundation.
This is probably a good one - http://www.adafruit.com/products/961
Plug this into one of the ports on the Raspberry Pi and use the other for the wifi dongle.
This will give you two extra ports for your mouse and keyboard.
Use logitech or intex USB hub and connect it the USB on the PI. The only issue is you must ensure that the power you supply to the pi is 5 Volts only and at least 1000mA otherwise, when you connect too many devices to the pi, it will stop responding to at least one of the devices.
From personal experience, I used my laptop for power supply, but the laptop USB is limited to providing 500mA and not more unless required. When I connected the Wifi dongle, keyboard and mouse, the mouse failed and the dongle was not getting detected. I removed the dongle and the mouse started to work again.