When I wanted to download Ubuntu 12.10 from ubuntu.com, I was asked to make a donation. However, there is only a PayPal option to make the payment. But I don't use PayPal. Is there any other option to make the payment?
You do not have to actually have a PayPal account in order to donate using PayPal. You can use your credit/debit card to donate. After clicking the "Pay with PayPal" button, you'll get another screen. Click "Pay with your debit or credit card as a PayPal guest."
Now, if you just hate PayPal, and refuse to use it at all, I can't help you there! :)
Currently you can only donate to Canonical directly with PayPal. According to Jono Bacon, "other payment mechanisms are currently being explored as we speak."
Another option for you is to donate to the projects behind applications that you often use or would like to support. Simply contact the software developers directly and ask them about it. Or send a real physical postcard to a developer where you thank him for his work, i am sure many open source developers appreciate some kind words just as much as money.