Have you heard of Money4Blogs? Well, they pay for links on your sidebar. I think something similar to LinkText from Linkworth. The only difference is, they pay for the link to remain at your sidebar for a year. So you will get one lumpsum payment.
You just need to submit your blog at Money4Blogs.com and they will email you how much they will pay you for a link. If you agree to it, place the link at your sidebar, inform them via email that you have done it and you will get your payment in less than a week.
The more traffic that you have, they offer is higher. PR does not really play an important role here. I got the same payment for my PR4 & PR3 blogs and a blogger with PR0 but have more traffic, get higher offer than mine!