Difference between LLC and MAC sublayers of a data link layer

http://www.cs.tut.fi/kurssit/83450/english/lec4.pdf

Here is a link explaining the MAC sublayer function, also goes into a little detail on LLC layer.

http://www.100vg.com/white/mac.htm

Here is a little  more indepth explanation of both.

http://www.firewall.cx/osi-encap-decap.php

Basically the IEEE split the layer 2 of the OSI model into the MAC and LLC sublayer for more compatability with newer technologies. The MAC layer is responsible for identifying the physical address of the computer sending or receiving packets and determines how the packet is placed on the media I.E. what network is it going into -- ethernet, token ring, fiddi, etc. It is a 6byte or 48 bit code that is encapsulated in the packets. This allows the receiving computer to know who sent the packet. This is totally different from an IP address (which is a layer 3 protocol). Two computers on the Internet and throughout the networks can have the same IP address (internally to the network), but cannot have the same MAC address (not supposed to anyway). When the packet gets to a network that the IP address has brought it to, there is a broadcast for the MAC address that matches the packet (in very basic terms) the computer that has the matching MAC address accepts the packet and processes it -- the rest ignore it. The LLC layer will determine what protocol is being use and ports for upper layer processing (on the way up) it also adds error checking and a DSAP and SSAP addressing components (source and destination information about the computers involved) Basically, it will let upper layers of the OSI model know who sent the packet and what protocols and ports it is intended for. You have to really understand what is going on in the whole OSI model to appreciate what these two layers do. I think the Cisco curriculum is the best and easiest to understand for learning the OSI model. It will take you a few times to REALLY start to get a grasp of what is going on within it. Hope this helps! ;)

Arut,
The whole concept of the OSI model is to segregate different functionality of communication to different layers..
I'm sure you know by now that the network layer (where the IP, IPX and the like ) is responsible for routing and finding routes for your packets to arrive to their destination. Except, when you visualize this, IP for instance, only gives you the final destination. For the packet to get there, it needs to know what the next hop is, hence come in the Data Link layer.
The Data Link layer is subdivided into 2 parts: MAC (Medium Access Control) and LLC (Logical Link Control).
In short, MAC defines how packets are placed on the medium, the physical addressing and some form of error detection and or correction. Bear in mind that you might have different topologies in networks such as a star network, ring or even bus network, running protocols such as Ethernet, Token Ring or other.. these protocols have different access methods to the physical layer, the most popular being CSMA/CD (Carrier Sense Multiple Access with Collision Detection).
Comes in the LLC. The LLC hides the MAC sublayer differences to the layer just above it: the network layer. Thus every IP packet will be formatted the same, whether the underlying network is Ethernet or Token ring or anything else for that matter.
There's a myriad of other protocols that go in (SAP, SNAP), but basically, what you have to remember is they have been made so that different formats of MAC protocols can co-exist in the same format.
The combination of both the two layers, LLC and MAC, provide the connectivity needed to go out to the infamous next hop.

Good sources for this topic is:
1- Computer Networks and Internets by Comer
2- CCNA prep book by Todd Lammle

If you're interested in the protocols in general, somewhere to start is http://www.protocols.com