HT Games
SkypeOut
While Skype is free for Skype-to-Skype calls to those who already have Skype accounts, you can also use your PSP to make phone calls to any number, just like a real phone. Since it costs money to call non-Skype users, you'll need to purchase Skype credits under your username through the Skype website. Once you have credits in place and you're within range of a Wi-Fi network, you can use your PSP to make any call to a valid phone number, whether it's a Skype user or not, by using the dial function. Calling rates vary depending on location.
SkypeIn
If you don't have a regular phone, you can give out a phone number if you choose to use SkypeIn. SkypeIn allows anyone to call your PSP, even if they're not using a Skype account. Again, you'll need to purchase your phone number on the Skype website and use credits to support calls, but once you've set up your SkypeIn account, you'll be given a real phone number that you can then distribute so friends and family can contact your PSP for a call.
Bluetooth
Since your PSP has built-in Wi-Fi capabilities, it can also support Bluetooth technology. If you have a Bluetooth device for your phone, it can also be used with your PSP while you make phone calls via Skype. This allows you to keep your hands free while you chat, especially considering that Skype on PSP can't support video chatting, since the PSP has no onboard webcam.
Sleep Settings
Unlike Skype on other applications such as smartphones and your laptop, you must have the application running and active if you want to make and receive calls on your Skype. This means you can't initiate Skype and then play a game while waiting for a call. This could mean drained batteries except that you can put your PSP into sleep mode so that it goes to sleep while still keeping Skype active to help save your battery. Just press upward quickly on the power button and your PSP screen will power down but leave Skype active so you don't miss a call. Start your PSP again by repeating the movement.