Question

I don't really know much tajweed as I only studied a year.  There seems to be a couple of different ways of pronouncing the word Allah, is that so or is it just the style of some readers?

Answer

Most likely you are referring to the tafkheem (heaviness) and tarqeeq (lightness) of the laam and following long alif  in the word, Allah.  When the word Allah is preceded by a fat-hah or dhammah, the laam and following alif become heavy, or acquire tafkheem.  When the word Allah is preceded by a kasrah, the laam and following alif are light.  Other than this, there is no difference in the pronunciation of the word Allah from one place to another in the Glorious Qur’an. 

Please also see the lesson on the tafkheem and tarqeeq of the Glorious name of Allah here