Erm well do you mean in terms of numbers, Or mechanics?
I'm not over-ly educated on holy at the moment (in terms of the last patch on beta). But from the look of things we still have the same concept in the sense we heal with Flash, Holy light and divine light. With Holy shock for building holy power, holy radiance for AoE and WoG / light of dawn as our holy power dump.
Some nice note-worth Holy changes though.. We can Backload 2 extra holy power and have 5 total saved up to use.
After you cast holy radiance, you get a buff that makes you holy shock do AoE healing.
Our mastery seems to affect more spells/scale better (It seems like everyone is saying it's one of our best secondary stats next to spirit or int).
We get a talent tier that lets us choose between a new version of sacred shield, or add a HoT to our WoG's.
And don't forget, Light of Dawn is losing the facing requirement - healing everyone within 30 yards instead of in front of you.
Judgment is no longer going to be mandatory either, Holy won't be required to keep up a buff for regen+haste any more but there are instead some talent choices related to judging if you liked that sort of gameplay. (Balance issues aside).
This is a really broad question so I'm just going to give simple points and if you have specific questions afterwards, ask them
-We can store two Holy Power now as our max is 5. This gives the ability to have a bit more burst in certain situations.
-Holy Radiance was nerfed and is no longer the AoE powerhouse it was. No more HoT portion, all upfront healing.
-Single target healing has remained about the same its always been. Talents make small changes to it
-The talent system is a huge change and probably something you should read up on entirely.
-Beacon takes heals from many more spells now and will do more of your healing because of it
-We don't have any new spells (with the exception of talents)