Hello
You can install either ESX 4 or ESX 3.5 on you laptop depending on the configuration of your laptop. Since you are a learner I will recommend you to get the ESXi 4 or ESXi 3.5 to start with.
ESX 4 or ESXi 4 requires 64 bit processor. So if you laptop is 64 bit, then you can install ESX4 or ESXi 4. If in case your laptop is 32 bit & supports VT (Virtualization Technology), you can still install ESX 4 or ESXi 4. For this you will have to go to your BIOS and enable VT.
If in case yours is only 32 bit processor with no VT support, then you have to settle with ESX or ESXi 3.5.
The best way to do this is to install vmware workstation on you laptop's OS. And then on vmware workstation you can install EXS host.
I hope this helps and do let me know if you need any further information on this. I am also new and just started learning a few weeks back.
Please mark ths answer correct, if this helps
Thanks
Riaz
kmriaz@hotmail.com
Riaz KM