Lighting for 90 gallon

[sdgoett at att_net]

I am still in the process of setting up my 90 gallon (I asked questions about 
lighting it with compact fluorescents a few weeks to months ago and got many 
responses - thanks).  Unfortunately I do not have much money to invest in the 
tank right now so I am not going to get CP lights just yet.  I do however 
have enough regular fluorescent fixtures to put on the tank to get 120watts 
(two 48" bulbs and two 24" bulbs).  I am still a bit confused as to the whole 
T8/T12 thing.  I am not sure if both can be used in my lights.  The one light 
with the 2 24" has T12s in it now the light made for 2 48" bulbs has no bulb 
in it and I don't know which it is supposed to have.  If I am going to use 
this for freshwater plants and fish which size bulb should I use (T8 or T12) 
and which K (5,000K, 10,000K, etc.)?  Specific brands and names would be nice 
to make shopping easier.  Keeping cost down would be nice too.  I do not 
particular like the yelowish lights, but if they are good for the plants I 
can probably mix them with whiter ones.

Scott