Are there clients that manage several alts? E.g. a desktop client that can manage, in a unified UI, Bitcoin, Namecoin, Litecoin, PPCoin...?
Ufasoft open source client can manage different alt-coins, most of them with same private keys.

https://bitcointalk.org/index.php?topic=58821.0

PD: be careful, some users have reported malware in Ufasoft mining software.