eplus runs a HSDPA-trial on few NodeBs in Düsseldorf an Leipzig, but even there HSDPA is only available to "friendly users" involved in their trial.

Having just testet CiscoVPN with my O2 postpaid SIM, I can confirm VPN works for O2 postpaid customers. However as Tchibo use another APN you can't conclude VPN is working with them.

Today Tchibo announced the introduction of a dayflat for € 2.95 (billed by calendar days and throttled after 1 GB). That's € 0.45 more expensive than Fonic, who also use the O2 network, but all in all Tchibo now offers the most attractive combination of data tariffs in a single SIM.
Details are already available at Germany - Tchibo - Prepaid Wireless Internet Access

Can you switch between different tariff options at will? e.g. if I want to do one month at data flat rate, the next at the 500MB bundle and in the last I only want to do 2 days at the daily rate? Is that all possible with the same SIM? Will that just cost me 20+10+3+3?

Yes, you can switch between options at will. But note that the monthly flatrate and the 500MB-pack are recurring subscriptions so you will first have to cancel the current option also by SMS in order to switch to another data option. That's all described in detail in the wiki page linked above.

Thanks. Just one more quick question. Does Tchibo block VoIP traffic?

No, they don't block VoIP. VoIP runs fine as far as you use a STUN-server, because on the O2 network subscribers get private IP addresses and all traffic needs to pass a NAT-Gateway, so your IP is not reachable from the internet.

That is great. So betamax will work fine via its Stun.

Thanks Inquisitor!

Just a small update on Tchibo:

They have recently converted their 500MB-datapack (€ 10/month) to a monthly flatrate with throttling to 64 KBit/s after exceeding 500MB.

So now there are four data options available to Tchibo customers:

• volume-based billing (activated by default) of € 0,24/MB (billed in 100KB-increments)
• "Internet-Tages-Flatrate" a dayflat for € 2.95/calendar day, throttled to 64 KBit/s after exceeding 1000MB/day
• "Internet Flatrate L" a monthly flatrate for € 9.95/30 days, throttled to 64 KBit/s after exceeding 500MB
• "Internet Flatrate XL" a monthly flatrate for € 19.95/30 days, throttled to 64 KBit/s after exceeding 5000MB (cheapest available in Germany as of June 2010)

Further Tchibo currently sell their Huawei E160 USB-modem with a Tchibo SIM-card and a free one-month-subscription of the "Internet Pack L" for just € 19.95. The modem is netlocked, but that's not an issue these days. ;-)

For details visit Germany - Tchibo - Prepaid Wireless Internet Access

Just a small correction: The current Tchibo offer for 20 EUR is with a Huawei E1550 stick, but this could also be case only in some of their shops.

Thanks. Actually the old E160 sold by Tchibo was better, as it has a connector for an external antenna and it also supports American 3G bands (at least 850 and 1900 MHz) while the E1550 is only capable of the European 2100 MHz-band. Anyway € 20 is a great deal if you consider only the free month is worth € 10, so practically the modem costs € 10.