SFIV: Help a noob please

[ColdAsIce]

Been reading through the Street Fighter IV thread but it is huge, can anyone give me some advice and really explain in a guide for dummys way the following:

Ultra Special
EX Specials

Is it possible to counter of avoid an Ultra attack when performed by the CPU?

Explain any other simple things I am missing.

Thanks.

 

[ColdAsIce]

Do you have to jump away just before the Ultra is executed?

From playing last night and especially against Seth, as far as I could tell the Ultra would just hit me with no warning.