The procedure for porting a SIM card from a pay-as-you-go phone to an iPhone 4 is well documented (example 1, example 2, config tool for iOS 5). This is a nice option for people mostly on WiFi who use a small number of minutes (or VoIP), because with AT&T GoPhone plans, you can keep network costs down toward $100/year.
Is there a similar procedure for porting to a high-end Android phone? For example, can you buy a $3 GoPhone from Best Buy, buy an unlocked or AT&T Samsung Galaxy S II off eBay, move the SIM card into the Galaxy, and expect it to work? Other than ensuring the GoPhone plan has a data bundle feature, what other configuration is required?
If you have an unlocked phone, I don't think there should be any problem. The SIM card for GoPhone is apparently just a regular prepaid SIM card and is not tied to the phone it is sold with. If the phone doesn't recognize the APN for 3G, just go to Settings > Wireless and Networks > Mobile Networks > Access point Names and enter the appropriate access point settings manually.
Settings > Wireless and Networks > Mobile Networks > Access point Names
How can I add and manage contacts on a SIM card with an Android phone (HTC Magic)? I'm aware of 1 application which is capable of doing this but it cost 4€ for SIMPLY managing SIM contacts o_O
The default (well, default on my Samsung Galaxy S - I guess default in Android doesn't mean much) contact manager can do a part of this. When creating a new contact, it gives the option of storing it on the SIM, Phone memory, or a linked account (like Google).
There's the option of copying contacts from SIM to Phone or Phone to SIM (Contacts->Menu->more -> Copy contacts). Import/Export is in the same spot.
I know these suggestions aren't quite what you're looking for. I don't know if contacts can be stored on a SIM card in different ways depending on the Phone. From what I've seen the software that comes with Android phones might (depending on manufacturer) let you move contacts around.
I wanted to delete some contacts on my SIM card on my HTC Sensation. I tried and tried and it didn't work. So I took out my old Nokia phone and it can read and write to the SIM card. Deleted the contacts I didn't want. It worked.
Don't store your contacts on the SIM card. There is no advantage in doing so. Modern smartphones are usually only able to import/export contacts stored on the SIM card.
The contact App from Android 4.0 on provides a feature which lets you import your contacts form SIM card to either Google contacts (which I highly recommend) or simply local phone contacts.
Open Contacts > Menu > Import/export > Import from SIM card
Furthermore the "Messaging" app of Android 4.0 is able to mange the text messages stored on the SIM card.
Is there some specific purpose or feature that would necessitate using the SIM?
If you have an Android phone then presumably you have a Google account. Any contacts added to your Google phone will by sync'd automatically to the signed in Google account unless you turn that function off. Why not just use Google to manage them? Then you can keep your SIM and sd card free of unneeded data and if you lose or trade up your phone you never lose your contacts. They would still exist in Google. Plus you can sign into Gmail to manage contacts that way.
New (manual) contacts should get backed up if your gmail account is linked, and they should show up in your gmail contacts.
But my old ones (on sim and phone before email was linked) did not. I had to copy the ones from my sim and phone to my SDcard by going into contacts (people) then menu -> export to SD (as for example SIM.vcf).
menu -> export
And after that menu -> import to (my email) linked gmail address. And i just told it to import all vcf files on the SD.
menu -> import
And that was it, they were now all in my gmail contacts.