The PSJailbreak website is probably the safest place to get your Jail Break. If you are going to buy from someone off their site, it is going to be safe. Although, I would like ti say I am having my doubts about the 3.50 Jail Break. If you ask me, I think they are just trying to get people to pre-order, then take their money and run.
If you have 3.41 or lower, and you have an older ipod, I'd suggest you check out the ipod thread on the PSX forums. That is what I used to JB my PS3. If you need th elink, let me know.