the apps are the same for any version of the ipod touch (so long as it has the 2.x firmware upgrade) or any version of the iphone with he 2.x firmware upgrade.
some apps will not load on the Touch as it needs a phone signal or microphone or the GPS (excludes touch original), but normally they will load unless it needs the hardware and will tell you why,
Once you have bough an app, game or whatever you can load it onto any ipod or iphone paired to your computer - if you have 4 devices you only have to buy the app once..
iphones in the UK on contract rage from free to £149 and pAYG are £342.50.
NOTE: JAilbroken devices can not add apps as the itunes will reject jailbroken devices as valid and refuse to add. so if you jailbreak you are stuck with jailbreak apps.
Cydia (and other jailbreaks) have cause more problems for people than its worth.. (I never jailbreak but buy apps like Air sharing to enable limited disk use) as the only other extra is unapproved apps and background wallpapers (which are distracting).
NEVER JAILBREAK! It causes so many problems and yet adds nearly nothing!
the 2.2 software from apple is stable and works well and lets you add hundreds of apps (many free) from the itunes App Store, many with features available in jailbroken items.
Jail breaking became redundant when the 2.0 software was released as it add almost nothing to the ipods abilities (other than the ability to browse its file structure which also makes it less secure).
Jail breaking also voids the warranty and does cause many issues form files vanishing, memory leaks and loss, rebooting and even failing to boot.
Jailbroken ipods cause so many problems (just search on here for them). It alters the boot code so its not really an ipod at all.