Hi!
Iam new in here and new to game development. I've been working on a breakout game for which I wrote a simple editor. I would like to accomplish following features:

1. I want to store prebuilt levels on the iPhone.
2. The user should be able to edit and create new levels.
3. Keep data on updates (appstore).

So whats the best way to store these levels? PList, txt/xml, Core Data, SQLite?
Thanks in advance!
//Mikael

I'd go with the fastest and most simple way. As always KISS - Keep It Stupid Simple. In this case simple txt file will do. Easy to parse, and edit by hand. For example:

Smilediver's suggestion seconded. For storing block data like that, text files are always dead simple. You can easily edit them by hand with a text editor and they are trivial to read/write. Using a bitmap file (like a png or bmp file) might be a little easier to edit graphically, but aren't quite as easy to work with in code.

The other options you listed:
PList - Basically is a subset of XML with APIs that make it easy to read. Works well for structured data, but not so well for tilemaps.
XML - Libraries help, but XML is a pain to deal with.
Core Data, SQLite - Stay away from these unless you are storing massive amounts of data that changes often. They generally take quite a bit of code to set up, read or write data, and generally need lots of error handling code.

I will look into using plain text files. I let you know if it worked shortly =)
Thanks guys!
//Mikael