You can use Pooler's CPU miner (right side, download zip link), also known as Minerd. You may need to install Visual C++ on your system.
It is easy to find and download, does not use OpenCL (programming extension for graphics cards). With the mobile, I will assume that it is a laptop so CPU mining will make it really hot. Keep in mind if you do have PCIx16 there are versions of the slot that will make it not compatible with newer graphics cards. I currently have a system with version 1.0a and an older ATI version 2.0 card is not even seen to be plugged in on that board and works great in another system.
There is a limit for mining with how long Bitcoin has been out as to profitability. With pooled mining, CPU mining can be done with a Stratum Proxy run on your system as a form of buffer for mining to cut down the traffic (also known as get work requests) Minerd will do. It may take months or years before your first coin, but it can be done. Check your CPU by looking at the list of Intel CPUs here for expected rates with Minerd.
Others will tell you at the beginning that it's not enough to be worth having the systems tied down doing all that hashing due to power costs. They don't get the big picture and would not think of things like Build your own supercomputer out of Raspberry Pi boards.
With the Raspberry Pi running Minerd, each would get around 0.46 Khash/sec, so a 32 unit cluster would be estimated 15.36 Khash/sec at less than the power for the system to read this posting.
The option of upgrading to a newer system with a mining capable card, keeping what you got and getting more of them running Minerd, or some other option is open.
The ' big ' issue for mining is more than the hash rate your systems can do. It is if you can afford the power while it is mining. I have yet to see threads dealing with the new power generating tech out there that can power the mining rigs.
See Tiny, Plastic Wind Turbines Suitable for City Dwellers as an example.
I hope this answers your question and then some.