I think OP puts a very poorly ask question here as well as not elaborate exactly what he wants. However, I think this is what OP wants to ask.
He currently has 5.0.1 on his phone and he wants to jailbreak it. So, his questions are;
1. Once he jailbreak his phone, does the jailbreak wipe or delete anything from his phone?
2. Does jailbreaking tool just add Cydia to his phone without formatting his Iphone, another word, wipe everything off his phone.
The answer for both of the above questions is "No", it will not wipe or delete anything from your phone, you will not need to restore your phone before jailbreaking. However, 5.0.1 is a tethered jailbreak.
Please refer to http://www.iclarified.com and/or redmondpie.com for tutorial and information about tethered jailbreak before you proceed with this.
Like Labman & Rick, I have a hang over as well. So, If I have not answered your questions above, then you will have to elaborate more on your questions to all of us.