OK, the rules regarding money transfers:
The Argentine government withholds 30% of any money sent into Argentina for 1 year. This is to avoid currency speculation. The only exception to this rule is for the purchase of property. However, the amount transferred in cannot exceed the value of the property and the bank cannot release the funds until they have seen the purchase contract and until you sign it.
Any money sent into Argentina is converted into pesos and then if you want dollars, it is converted back. The problem is that non-residents cannot legally buy more than us$5000 per month. So when you buy a property, it's officially the seller that converts the money back into dollars.
A normal bank cannot and will not allow non-residents to transfer money into the country for the purchase of a property. You have to use a bank that is legally registered to perform this service. Most foreigners don't know this and are illegally bringing money into the country using 'exchange houses' or 'private banks'. There are only a couple of banks that are registered to do this. One of these is Banco Piano, on San Martin between Corrientes and Sarmiento (i think). it charges 2% including all fees and currency exchanges.
You can bring up to us$10,000 per trip into the country in cash.
If you want to bring in large sums of money for non-property related business (eg renovations) it's better to do so illegally. No one will ever find out as there's nothing the tax authorities can physically see. However, at some point the central bank is going to to start asking questions as to how all these foreigners bought expensive properties without any of the money going through them (and therefore stiffing them for money).
If you buy a property and then sell within a year, the government will withhold 30% until the year is finished.
The above are the rules for NON-residents. Once you get residency it all changes. If you're a rentista or pensionista who needs to prove their income per month then a normal bank will be able to help. You could also simply take the cash out of an ATM and keep the receipts as proof.
Once you have residency you can bring in and send out as much money as you want without the 30% withholding through a normal bank. The catch with this is that many banks require you to be a customer for 6 months before they allow you to make international transfers. It's best to open an account as soon as possible whether you have residency or not. You just need a CDI and proof of domicile. Banco Frances is the bank that is most receptive to non-residents.
I got this info from my friend matt at www.realba.blogspot.com who's been dealing with these issues for quite a while now. I don't think he'll be around much longer in buenos aires as it would appear he's heading to chile for business soon but i should think he'll be happy to help if he can with any questions you might have.
dtz