Any remote flash can be triggered with a long cord in the camera body sync socket or hot shoe mounted sync cord (which satisfies the criteria in your question). To be truly wireless, I can think of two options.
1) A small, hot shoe mounted slave flash triggers the remote flash when a sensor attached to the remote sees the slave go off. Downside: Anyone else's nearby flash will likely trigger your remote, distance is limited, slave may not work in high ambient light.
2) A camera mounted radio transponder signals a receiver connected to the remote. Good range, ambient light not a factor. Downside: will cost about $400.
Yes, you can. It has a Hot Shoe Mount.
Any Speedlite!
There are quite a few different models of the Canon Speedlite Flash camera. Reviews for each of the different models can be found on Amazon. These reviews are written by members of the public who have used these cameras. Further reviews and ratings can be found on the Digital Camera School website.
Yep!
Canon Speedlites are accessories for Canon cameras that provide light for dark conditions as well as other features for professional photographers. Canon Speedlites are available for purchase from Canon's official website or through specialty camera shops.
Yes, it is. :-)
Seems as if the Speedlite 420ex can't keep up with the speed of the 50d. Many missed flashes.
The Canon Powershot SD430 Digital ELPH Wireless can print wirelessly via your computer.
The Canon photo wireless printer is very good, and can even print photos directly from a camera.
It does not work with my xsi - the picture is over exposed
Speedlite is the trade name for Canon's line of external flashes. The series of flashes include the Speedlite 90 EX, 220 EX, 270 EX and 270 EX II, 320 EX and the 380 EX.
Yes, It will.