MRFIZX  This is awesome! I was just about to go through all of the hassle of using a Jailbreak-utilizing program and even lugged an Intel iMac home, then this came out! Ambrosia's made a great little piece of software that does exactly what it's supposed to--well! I just hope that Apple doesn't come out with something similar on the 5th! I do think it should've been in the $5-8 range for its limited nature, however.  
(Version 1.0)

MRFIZX  I've used this with my regular-level high school physics students with no problems for the past year or so. They can use the program without much instruction from me, which goes to show how simple the program is to use (they couldn't use Excel to save their grades, let alone lives!). I can read their data, they get their labs done more quickly and accurately, and it's all done with a minimum of effort on everyone's part. And until the graphing features of Pages/Keynote match Graph Sketcher's ease and control, this will be my graphing program of choice.  
(Version 1.0)

MRFIZX  As a physics teacher using equations in almost every presentation, test, worksheet, etc., I can say that this program definitely beats learning/using LaTeX or even using Word's Equation Editor then copying and pasting. It's updated regularly, and the developers take suggestions and implement them quickly. It's easily customizable and you can save all of your equations for later (and easy) use.  
(Version 5.33)

MRFIZX  I've found that Bookpedia (and the other 'pedia apps) are just faster. Even though they aren't an all-in-one solution like Delicious Library. It took a little over a minute to scan each book (by Firewire camera, not iSight) in Delicious, but only half that in Bookpedia. Still a long time in my opinion (with about 1000 books left to scan in), but less time total. Scrolling and searching time was even worse in Delicious [this was on an iMac G5 with RAM maxed at 2G, BTW]. Both apps need some speed tweaking, but Bookpedia needs less.  
(Version 2.3)