Hi, Polarbebe!
Don't worry. Look at the total of your "Apps + Other". They should stay pretty consistent, but the balance between them changes quite frequently - especially if you have a lot of applications. What's going on in 2.1 is that it has a bug where it sometimes misidentifies some Apps as Other. Each time you update, install, or delete an App (or sometimes, just unplug and re-plug your iPhone), you'll see this results in changing numbers.
For example, my phone's running near the limit for installed applications, and the proper totals are 1.16 GB of Apps, and 335 MB of Other. In a single day, I'll see those totals radically change individually, like to 150 MB for Apps and 1.35 GB of Other, or other odd combinations which yield the same total storage.
This constant flipping is confusing, but it's just the totals on iTunes' iPhone Summary page that are buggy. Look at the total for Apps + Other, and you'll see that things are in fact just fine.
Cheers!
Mark