Systems these days are normally configured to use AHCI as default within BIOS. If BIOS is already set to AHCI (or AHCI+RAID), you don't need to do anything. If BIOS is set to IDE, it may or may not be a simple thing to change to AHCI (or AHCI+RAID) depending on what drivers were installed within the OS itself. Again, usually you have drivers for both IDE and AHCI (or AHCI+RAID) installed by the OS but if you don't have both sets of drivers, you will get a blue screen restart if you change from IDE to AHCI (or AHCI+RAID). So best to check your BIOS and see what it is set to. I'll assume it is set to AHCI (or AHCI+RAID) in BIOS.
Oh, and the reason we usually set BIOS to AHCI (or AHIC+RAID) is because it provides some useful SSD features like TRIM which helps with maintaining the performance of the SSD over time.
Now i would perform a backup before doing anything else. Luckily Windows 7 includes the "MS Backup and Restore" application. I expect that Windows 8 also includes similar but i'll let you navigate the stupid Win8 UI. I'll assume you are familiar with Windows 7 and can translate this knowledge to Windows8. And I don't bother with the Dell bloatware backup apps.
1) Disable 'system restore', then if you have 8GB or more RAM, turn off windows page file. Both can be done from 'advanced system properties'.
2) Perform a disc cleanup, defragment the system drive.
3) Lastly shrink the system volume (c:\) using disk management.
Doing this will make the C:\ much much smaller than the original HDD partition. In my case, my system drive (C:\) which was 300GB in size, would have been too big to fit on my 120GB SSD (even after disk cleanup, defrag & volume shrink). By doing the above, i managed to shrink it to <42GB in size which makes for a much smaller backup and fits nicely onto my Intel 120GB SSD.
Now you can finally make your backup**
4) Use 'MS backup & restore' to create a 'system repair' CD and also create a 'System Image' to a non bootable external (USB) HDD.
5) Remove the internal HDD and install the new SSD. Leave the external HDD plug in.
6) Boot your system using the 'System repair CD' you previously created.
7) You should now be able to point to the previously created 'System Image' located on the external HDD when performing a restore/recovery (can't remember the correct term -brain fade)
8) The restore process will reboot the system which will now boot from the SSD.
You are now running from the SSD but we are not finished yet.
9) Extend the SSD c:\ volume using disk management.
10) Turn on 'system restore' and the 'page file'.
Also you can go to www.thessdreview.com and look under "Guides" for some SSD optimization and performance tuning hints that you could then apply. Me i didn't bother with any tuning above what the Intel SSD Toolbox provided (turned off defragment schedule) I think the Samsung tool has similar optimization features.
The benefit of this process is that it tests your backup and gets you familiar with the backup process
If you don't have an external HDD you can use for your backups, i would recommend you buy one unless you don't value your personal data.
Now if you don't have an external HDD to use, the Samsung migration software may fail in cloning your 500GB HDD to your new 256GB SSD, though it depending on it's capabilities. But if you use this tool after you shrink the partition (at this point **), it should work OK.
In my case, the Intel Migration Toolbox based on Acronis True Image would not back up my 300GB partition to my 160GB SSD.
Also be warned that Intel Migration Toolbox (ATI) did not play well with MS Backup & Restore so you may need to remove it after doing your migration. You could have a similar issue with the Samsung Tool.