Is there a way to connect my apple ball speakers to my MacBookPro? The speakers have a 2.5mm jack but the MacBook Pro has a USB port. Thanks!
You need a USB DAC (Digital Audio Converter).
I personally use a Behringer UCA202 to connect my iMac to my Bose Wave Radio (line input).
What's really nice about it is that it's powered off the USB port meaning it doesn't need an external power adapter. It also has both left and right inputs and outputs as well as a 3.5mm headphone connection. For best quality, you will want to use the RCA output. You will just need an RCA to 3.5mm adapter (second picture) to connect to your speakers.
If your speakers have 2.5mm you'll need to buy 2.5mm -> 3.5mm adapter (like this) to connect it with MacBook Pro
Do you mean the Apple "Pro Speakers" by Harmon Kardon? They have what looks like a standard 3.5mm (1/8inch) audio jack, but, unsurprisingly, the collar around the end makes it very difficult to plug into anything except the G4 'anglepoise' iMac they were designed for.
Also, if memory serves, they expect a higher output signal than is standard, so their audio 'profile' may not be optimal on other Macs.