What are the rear speaker sizes and the front speaker sizes? I looked it up and the front is 3.5" but I'm not very sure about it. The rear says to be 6.5" but I opened it today and the speakers measured 5.5" across, but if I measure it from the very edge of the speaker it measures 6", so I'm a bit confused right now. And, how do I go about changing the front speakers? If I can get my speaker size questions answered soon, that would be great since I'm planning to get new speakers.

Maybe you can find the information you need here:
http://www.installdr.com/

I've been to that site before. That site doesn't say what size speakers I have. If it does, then I didn't look for it well enough. But, that site only tells me how to install a radio for my car, but not speakers.

Try Crutchfield for help. The front speakers I think are the size you stated but the mounting holes are special. Some companies years ago made speakers with the special holes for this generation Camry.

1991 camry's are the same as 89's and i replaced mine, 3.5"s in the front. 6.5"s in the rear deck.

as for getting to the front ones you literally have to take the whole dash off. start with taking out the glove box then continue with the bolts underneath the dash. If i remember correctly you'll need a 10mm socket wrench.

i did mine all myself and since it was like a shot in the dark it took me a whole day. make sure you get the speakers you really want. a month later my new reciever blew my new ones so i took them back for better ones. I Highly recommend the 3.5" alpine type-s coax.